BusyBox - The Swiss Army Knife of Embedded Linux
busybox <applet> [arguments...] # or
<applet> [arguments...] # if symlinked
BusyBox combines tiny versions of many common UNIX utilities into a single small executable. It provides minimalist replacements for most of the utilities you usually find in GNU coreutils, util-linux, etc. The utilities in BusyBox generally have fewer options than their full-featured GNU cousins; however, the options that are included provide the expected functionality and behave very much like their GNU counterparts.
BusyBox has been written with size-optimization and limited resources in mind. It is also extremely modular so you can easily include or exclude commands (or features) at compile time. This makes it easy to customize your embedded systems. To create a working system, just add /dev, /etc, and a Linux kernel. BusyBox provides a fairly complete POSIX environment for any small or embedded system.
BusyBox is extremely configurable. This allows you to include only the components you need, thereby reducing binary size. Run 'make config' or 'make menuconfig' to select the functionality that you wish to enable. Then run 'make' to compile BusyBox using your configuration.
After the compile has finished, you should use 'make install' to install BusyBox. This will install the 'bin/busybox' binary, in the target directory specified by CONFIG_PREFIX. CONFIG_PREFIX can be set when configuring BusyBox, or you can specify an alternative location at install time (i.e., with a command line like 'make CONFIG_PREFIX=/tmp/foo install'). If you enabled any applet installation scheme (either as symlinks or hardlinks), these will also be installed in the location pointed to by CONFIG_PREFIX.
BusyBox is a multi-call binary. A multi-call binary is an executable program that performs the same job as more than one utility program. That means there is just a single BusyBox binary, but that single binary acts like a large number of utilities. This allows BusyBox to be smaller since all the built-in utility programs (we call them applets) can share code for many common operations.
You can also invoke BusyBox by issuing a command as an argument on the command line. For example, entering
/bin/busybox ls
will also cause BusyBox to behave as 'ls'.
Of course, adding '/bin/busybox' into every command would be painful. So most people will invoke BusyBox using links to the BusyBox binary.
For example, entering
ln -s /bin/busybox ls ./ls
will cause BusyBox to behave as 'ls' (if the 'ls' command has been compiled into BusyBox).
If you invoke BusyBox with no arguments, it will provide you with a list of the applets that have been compiled into your BusyBox binary.
Most BusyBox applets support the --help argument to provide a terse runtime description of their behavior. If the CONFIG_FEATURE_VERBOSE_USAGE option has been enabled, more detailed usage information will also be available.

Listen to ACPI events and spawn specific helpers on event arrival
Options:
-d Do not daemonize and log to stderr -c DIR Config directory [/etc/acpi] -e FILE /proc event file [/proc/acpi/event] -l FILE Log file [/var/log/acpid]
Accept and ignore compatibility options -g -m -s -S -v
addgroup [-g GID] [user_name] group_name
Add a group or add a user to a group
Options:
-g GID Group id -S Create a system group
adduser [OPTIONS] user_name
Add a user
Options:
-h DIR Home directory -g GECOS GECOS field -s SHELL Login shell -G GRP Add user to existing group -S Create a system user -D Do not assign a password -H Do not create home directory -u UID User id
adjtimex [-q] [-o offset] [-f frequency] [-p timeconstant] [-t tick]
Read and optionally set system timebase parameters. See adjtimex(2)
.
Options:
-q Quiet -o offset Time offset, microseconds -f frequency Frequency adjust, integer kernel units (65536 is 1ppm) (positive values make clock run faster) -t tick Microseconds per tick, usually 10000 -p timeconstant
ar [-o] [-v] [-p] [-t] [-x] ARCHIVE FILES
Extract or list FILES from an ar archive
Options:
-o Preserve original dates -p Extract to stdout -t List -x Extract -v Verbose
| arp | |
| [-vn] | [-H type] [-i if] -a [hostname] |
| [-v] | [-i if] -d hostname [pub] |
| [-v] | [-H type] [-i if] -s hostname hw_addr [temp] |
| [-v] | [-H type] [-i if] -s hostname hw_addr [netmask nm] pub |
| [-v] | [-H type] [-i if] -Ds hostname ifa [netmask nm] pub |
Manipulate ARP cache
Options:
-a Display (all) hosts -s Set new ARP entry -d Delete a specified entry -v Verbose -n Don't resolve names -i IF Network interface -D Read <hwaddr> from given device -A, -p AF Protocol family -H HWTYPE Hardware address type
arping [-fqbDUA] [-c count] [-w timeout] [-I dev] [-s sender] target
Send ARP requests/replies
Options:
-f Quit on first ARP reply -q Quiet -b Keep broadcasting, don't go unicast -D Duplicated address detection mode -U Unsolicited ARP mode, update your neighbors -A ARP answer mode, update your neighbors -c N Stop after sending N ARP requests -w timeout Time to wait for ARP reply, in seconds -I dev Interface to use (default eth0) -s sender Sender IP address target Target IP address
awk [OPTIONS] [AWK_PROGRAM] [FILE]...
Options:
-v VAR=VAL Set variable -F SEP Use SEP as field separator -f FILE Read program from file
basename FILE [SUFFIX]
Strip directory path and .SUFFIX from FILE
beep -f freq -l length -d delay -r repetitions -n
Options:
-f Frequency in Hz -l Length in ms -d Delay in ms -r Repetitions -n Start new tone
blkid
Print UUIDs of all filesystems
brctl COMMAND [BRIDGE [INTERFACE]]
Manage ethernet bridges
Commands:
show Show a list of bridges addbr BRIDGE Create BRIDGE delbr BRIDGE Delete BRIDGE addif BRIDGE IFACE Add IFACE to BRIDGE delif BRIDGE IFACE Delete IFACE from BRIDGE setageing BRIDGE TIME Set ageing time setfd BRIDGE TIME Set bridge forward delay sethello BRIDGE TIME Set hello time setmaxage BRIDGE TIME Set max message age setpathcost BRIDGE COST Set path cost setportprio BRIDGE PRIO Set port priority setbridgeprio BRIDGE PRIO Set bridge priority stp BRIDGE [1|0] STP on/off
bunzip2 [OPTIONS] [FILE]
Uncompress FILE (or standard input if FILE is '-' or omitted)
Options:
-c Write to standard output -f Force
bzcat FILE
Uncompress to stdout
bzip2 [OPTIONS] [FILE]...
Compress FILE(s) with bzip2 algorithm. When FILE is '-' or unspecified, reads standard input. Implies -c.
Options:
-c Write to standard output -d Decompress -f Force -1..-9 Compression level
cal [-jy] [[month] year]
Display a calendar
Options:
-j Use julian dates -y Display the entire year
cat [-u] [FILE]...
Concatenate FILE(s) and print them to stdout
Options:
-u Use unbuffered i/o (ignored)
catv [-etv] [FILE]...
Display nonprinting characters as ^x or M-x
Options:
-e End each line with $ -t Show tabs as ^I -v Don't use ^x or M-x escapes
chat EXPECT [SEND [EXPECT [SEND...]]]
Useful for interacting with a modem connected to stdin/stdout. A script consists of one or more "expect-send" pairs of strings, each pair is a pair of arguments. Example: chat '' ATZ OK ATD123456 CONNECT '' ogin: pppuser word: ppppass '~'
chattr [-R] [-+=AacDdijsStTu] [-v version] files...
Change file attributes on an ext2 fs
Modifiers:
- Remove attributes + Add attributes = Set attributes Attributes:
A Don't track atime a Append mode only c Enable compress D Write dir contents synchronously d Do not backup with dump i Cannot be modified (immutable) j Write all data to journal first s Zero disk storage when deleted S Write file contents synchronously t Disable tail-merging of partial blocks with other files u Allow file to be undeleted Options:
-R Recursively list subdirectories -v Set the file's version/generation number
chgrp [-RhLHPcvf]... GROUP FILE...
Change the group membership of each FILE to GROUP
Options:
-R Recurse -h Affect symlinks instead of symlink targets -L Traverse all symlinks to directories -H Traverse symlinks on command line only -P Do not traverse symlinks (default) -c List changed files -v Verbose -f Hide errors
chmod [-Rcvf] MODE[,MODE]... FILE...
Each MODE is one or more of the letters ugoa, one of the symbols +-= and one or more of the letters rwxst
Options:
-R Recurse -c List changed files -v List all files -f Hide errors
chown [-RhLHPcvf]... OWNER[<.|:>[GROUP]] FILE...
Change the owner and/or group of each FILE to OWNER and/or GROUP
Options:
-R Recurse -h Affect symlinks instead of symlink targets -L Traverse all symlinks to directories -H Traverse symlinks on command line only -P Do not traverse symlinks (default) -c List changed files -v List all files -f Hide errors
chpasswd [--md5|--encrypted]
Read user:password from stdin and update /etc/passwd
Options:
-e,--encrypted Supplied passwords are in encrypted form -m,--md5 Use MD5 encryption instead of DES
| chpst [-vP012] [-u USER[:GRP]] [-U USER[:GRP]] [-e DIR] | |
| [-/ DIR] [-n NICE] [-m BYTES] [-d BYTES] [-o N] | |
| [-p N] [-f BYTES] [-c BYTES] PROG ARGS |
Change the process state and run PROG
Options:
-u USER[:GRP] Set uid and gid -U USER[:GRP] Set $UID and $GID in environment -e DIR Set environment variables as specified by files in DIR: file=1st_line_of_file -/ DIR Chroot to DIR -n NICE Add NICE to nice value -m BYTES Same as -d BYTES -s BYTES -l BYTES -d BYTES Limit data segment -o N Limit number of open files per process -p N Limit number of processes per uid -f BYTES Limit output file sizes -c BYTES Limit core file size -v Verbose -P Create new process group -0 Close standard input -1 Close standard output -2 Close standard error
chroot NEWROOT [PROG [ARGS]]
Run PROG with root directory set to NEWROOT
chrt [OPTIONS] [PRIO] [PID | PROG [ARGS]]
Manipulate real-time attributes of a process
Options:
-p Operate on pid -r Set scheduling policy to SCHED_RR -f Set scheduling policy to SCHED_FIFO -o Set scheduling policy to SCHED_OTHER -m Show min and max priorities
chvt N
Change the foreground virtual terminal to /dev/ttyN
cksum FILES...
Calculate the CRC32 checksums of FILES
clear
Clear screen
cmp [-l] [-s] FILE1 [FILE2 [SKIP1 [SKIP2]]]
Compares FILE1 vs stdin if FILE2 is not specified
Options:
-l Write the byte numbers (decimal) and values (octal) for all differing bytes -s Quiet
comm [-123] FILE1 FILE2
Compare FILE1 to FILE2, or to stdin if - is specified
Options:
-1 Suppress lines unique to FILE1 -2 Suppress lines unique to FILE2 -3 Suppress lines common to both files
cp [OPTIONS] SOURCE DEST
Copy SOURCE to DEST, or multiple SOURCE(s) to DIRECTORY
Options:
-a Same as -dpR -d,-P Preserve links -H,-L Dereference all symlinks (default) -p Preserve file attributes if possible -f Force overwrite -i Prompt before overwrite -R,-r Recurse -l,-s Create (sym)links
cpio -[tiopdmvu] [-F FILE] [-H newc]
Extract or list files from a cpio archive, or create a cpio archive Main operation mode:
-t List -i Extract -o Create -p Passthrough Options:
-d Make leading directories -m Preserve mtime -v Verbose -u Overwrite -F Input file -H Define format
crond -fbS -l N -d N -L LOGFILE -c DIR
-f Foreground -b Background (default) -S Log to syslog (default) -l Set log level. 0 is the most verbose, default 8 -d Set log level, log to stderr -L Log to file -c Working dir
crontab [-c DIR] [-u USER] [-ler]|[FILE]
-c Crontab directory -u User -l List crontab -e Edit crontab -r Delete crontab FILE Replace crontab by FILE ('-': stdin)
cryptpw [OPTIONS] [PASSWORD] [SALT]
Crypt the PASSWORD using crypt(3)
Options:
-P,--password-fd=NUM Read password from fd NUM -m,--method=TYPE Encryption method TYPE -S,--salt=SALT
cut [OPTIONS] [FILE]...
Print selected fields from each input FILE to standard output
Options:
-b LIST Output only bytes from LIST -c LIST Output only characters from LIST -d CHAR Use CHAR instead of tab as the field delimiter -s Output only the lines containing delimiter -f N Print only these fields -n Ignored
date [OPTIONS] [+FMT] [TIME]
Display time (using +FMT), or set time
Options:
[-s] TIME Set time to TIME -u Work in UTC (don't convert to local time) -R Output RFC-822 compliant date string -I[SPEC] Output ISO-8601 compliant date string SPEC='date' (default) for date only, 'hours', 'minutes', or 'seconds' for date and time to the indicated precision -r FILE Display last modification time of FILE -d TIME Display TIME, not 'now' -D FMT Use FMT for -d TIME conversion
Recognized TIME formats:
hh:mm[:ss] [YYYY.]MM.DD-hh:mm[:ss] YYYY-MM-DD hh:mm[:ss] [[[[[YY]YY]MM]DD]hh]mm[.ss]
dc expression...
Tiny RPN calculator. Operations: +, add, -, sub, *, mul, /, div, %, mod, **, exp, and, or, not, eor, p - print top of the stack (without altering the stack), f - print entire stack, o - pop the value and set output radix (value must be 10 or 16). Examples: 'dc 2 2 add' -> 4, 'dc 8 8 * 2 2 + /' -> 16.
| dd [if=FILE] [of=FILE] [ibs=N] [obs=N] [bs=N] [count=N] [skip=N] | |
| [seek=N] [conv=notrunc|noerror|sync|fsync] |
Copy a file with converting and formatting
Options:
if=FILE Read from FILE instead of stdin of=FILE Write to FILE instead of stdout bs=N Read and write N bytes at a time ibs=N Read N bytes at a time obs=N Write N bytes at a time count=N Copy only N input blocks skip=N Skip N input blocks seek=N Skip N output blocks conv=notrunc Don't truncate output file conv=noerror Continue after read errors conv=sync Pad blocks with zeros conv=fsync Physically write data out before finishing
Numbers may be suffixed by c (x1), w (x2), b (x512), kD (x1000), k (x1024), MD (x1000000), M (x1048576), GD (x1000000000) or G (x1073741824)
deallocvt [N]
Deallocate unused virtual terminal /dev/ttyN
delgroup [USER] GROUP
Delete group GROUP from the system or user USER from group GROUP
deluser USER
Delete USER from the system
devmem ADDRESS [WIDTH [VALUE]]
Read/write from physical address
ADDRESS Address to act upon WIDTH Width (8/16/...) VALUE Data to be written
df [-Pkmhai] [-B SIZE] [FILESYSTEM...]
Print filesystem usage statistics
Options:
-P POSIX output format -k 1024-byte blocks (default) -m 1M-byte blocks -h Human readable (e.g. 1K 243M 2G) -a Show all filesystems -i Inodes -B SIZE Blocksize
dhcprelay CLIENT_IFACE[,CLIENT_IFACE2...] SERVER_IFACE [SERVER_IP]
Relay DHCP requests between clients and server
diff [-abdiNqrTstw] [-L LABEL] [-S FILE] [-U LINES] FILE1 FILE2
Compare files line by line and output the differences between them. This implementation supports unified diffs only.
Options:
-a Treat all files as text -b Ignore changes in the amount of whitespace -d Try hard to find a smaller set of changes -i Ignore case differences -L Use LABEL instead of the filename in the unified header -N Treat absent files as empty -q Output only whether files differ -r Recursively compare subdirectories -S Start with FILE when comparing directories -T Make tabs line up by prefixing a tab when necessary -s Report when two files are the same -t Expand tabs to spaces in output -U Output LINES lines of context -w Ignore all whitespace
dirname FILENAME
Strip non-directory suffix from FILENAME
dmesg [-c] [-n LEVEL] [-s SIZE]
Print or control the kernel ring buffer
Options:
-c Clear ring buffer after printing -n LEVEL Set console logging level -s SIZE Buffer size
dnsd [-c config] [-t seconds] [-p port] [-i iface-ip] [-d]
Small static DNS server daemon
Options:
-c Config filename -t TTL in seconds -p Listening port -i Listening ip (default all) -d Daemonize
dos2unix [OPTION] [FILE]
Convert FILE in-place from DOS to Unix format. When no file is given, use stdin/stdout.
Options:
-u dos2unix -d unix2dos
dpkg [-ilCPru] [-F option] package_name
Install, remove and manage Debian packages
Options:
-i Install the package -l List of installed packages -C Configure an unpackaged package -F depends Ignore dependency problems -P Purge all files of a package -r Remove all but the configuration files for a package -u Unpack a package, but don't configure it
du [-aHLdclsxhmk] [FILE]...
Summarize disk space used for each FILE and/or directory. Disk space is printed in units of 1024 bytes.
Options:
-a Show file sizes too -H Follow symlinks on command line -L Follow all symlinks -d N Limit output to directories (and files with -a) of depth < N -c Show grand total -l Count sizes many times if hard linked -s Display only a total for each argument -x Skip directories on different filesystems -h Sizes in human readable format (e.g., 1K 243M 2G ) -m Sizes in megabytes -k Sizes in kilobytes (default)
dumpkmap > keymap
Print a binary keyboard translation table to standard output
dumpleases [-r|-a] [-f LEASEFILE]
Display DHCP leases granted by udhcpd
Options:
-f,--file=FILE Leases file to load -r,--remaining Interpret lease times as time remaining -a,--absolute Interpret lease times as expire time
echo [-neE] [ARG...]
Print the specified ARGs to stdout
Options:
-n Suppress trailing newline -e Interpret backslash-escaped characters (i.e., \t=tab) -E Disable interpretation of backslash-escaped characters
ed
eject [-t] [-T] [DEVICE]
Eject specified DEVICE (or default /dev/cdrom)
Options:
-s SCSI device -t Close tray -T Open/close tray (toggle)
env [-iu] [-] [name=value]... [PROG [ARGS]]
Print the current environment or run PROG after setting up the specified environment
Options:
-, -i Start with an empty environment -u Remove variable from the environment
envdir dir prog args
Set various environment variables as specified by files in the directory dir and run PROG
envuidgid account prog args
Set $UID to account's uid and $GID to account's gid and run PROG
expand [-i] [-t NUM] [FILE|-]
Convert tabs to spaces, writing to standard output
Options:
-i,--initial Do not convert tabs after non blanks -t,--tabs=N Tabstops every N chars
expr EXPRESSION
Print the value of EXPRESSION to standard output
EXPRESSION may be:
ARG1 | ARG2 ARG1 if it is neither null nor 0, otherwise ARG2 ARG1 & ARG2 ARG1 if neither argument is null or 0, otherwise 0 ARG1 < ARG2 1 if ARG1 is less than ARG2, else 0. Similarly: ARG1 <= ARG2 ARG1 = ARG2 ARG1 != ARG2 ARG1 >= ARG2 ARG1 > ARG2 ARG1 + ARG2 Sum of ARG1 and ARG2. Similarly: ARG1 - ARG2 ARG1 * ARG2 ARG1 / ARG2 ARG1 % ARG2 STRING : REGEXP Anchored pattern match of REGEXP in STRING match STRING REGEXP Same as STRING : REGEXP substr STRING POS LENGTH Substring of STRING, POS counted from 1 index STRING CHARS Index in STRING where any CHARS is found, or 0 length STRING Length of STRING quote TOKEN Interpret TOKEN as a string, even if it is a keyword like 'match' or an operator like '/' (EXPRESSION) Value of EXPRESSION
Beware that many operators need to be escaped or quoted for shells. Comparisons are arithmetic if both ARGs are numbers, else lexicographical. Pattern matches return the string matched between \( and \) or null; if \( and \) are not used, they return the number of characters matched or 0.
fakeidentd [-fiw] [-b ADDR] [STRING]
Provide fake ident (auth) service
Options:
-f Run in foreground -i Inetd mode -w Inetd 'wait' mode -b ADDR Bind to specified address STRING Ident answer string (default: nobody)
false
Return an exit code of FALSE (1)
fbset [OPTIONS] [MODE]
Show and modify frame buffer settings
fbsplash -s IMGFILE [-c] [-d DEV] [-i INIFILE] [-f CMD]
Options:
-s Image -c Hide cursor -d Framebuffer device (default /dev/fb0) -i Config file (var=value): BAR_LEFT,BAR_TOP,BAR_WIDTH,BAR_HEIGHT BAR_R,BAR_G,BAR_B -f Control pipe (else exit after drawing image) commands: 'NN' (% for progress bar) or 'exit'
fdflush DEVICE
Force floppy disk drive to detect disk change
fdformat [-n] DEVICE
Format floppy disk
Options:
-n Don't verify after format
fdisk [-ul] [-C CYLINDERS] [-H HEADS] [-S SECTORS] [-b SSZ] DISK
Change partition table
Options:
-u Start and End are in sectors (instead of cylinders) -l Show partition table for each DISK, then exit -b 2048 (for certain MO disks) use 2048-byte sectors -C CYLINDERS Set number of cylinders/heads/sectors -H HEADS
-S SECTORS
find [PATH...] [EXPRESSION]
Search for files. The default PATH is the current directory, default EXPRESSION is '-print'
EXPRESSION may consist of:
-follow Dereference symlinks -xdev Don't descend directories on other filesystems -maxdepth N Descend at most N levels. -maxdepth 0 applies tests/actions to command line arguments only -mindepth N Do not act on first N levels -name PATTERN File name (w/o directory name) matches PATTERN -iname PATTERN Case insensitive -name -path PATTERN Path matches PATTERN -regex PATTERN Path matches regex PATTERN -type X File type is X (X is one of: f,d,l,b,c,...) -perm NNN Permissions match any of (+NNN), all of (-NNN), or exactly (NNN) -mtime DAYS Modified time is greater than (+N), less than (-N), or exactly (N) days -mmin MINS Modified time is greater than (+N), less than (-N), or exactly (N) minutes -newer FILE Modified time is more recent than FILE's -inum N File has inode number N -user NAME File is owned by user NAME (numeric user ID allowed) -group NAME File belongs to group NAME (numeric group ID allowed) -depth Process directory name after traversing it -size N[bck] File size is N (c:bytes,k:kbytes,b:512 bytes(def.)). +/-N: file size is bigger/smaller than N -print Print (default and assumed) -print0 Delimit output with null characters rather than newlines -exec CMD ARG ; Run CMD with all instances of {} replaced by the matching files -prune Stop traversing current subtree -delete Delete files, turns on -depth option (EXPR) Group an expression
findfs LABEL=label or UUID=uuid
Find a filesystem device based on a label or UUID
flash_lock MTD_DEVICE OFFSET SECTORS
Lock part or all of an MTD device. If SECTORS is -1, then all sectors will be locked, regardless of the value of OFFSET
flash_unlock MTD_DEVICE
Unlock an MTD device
fold [-bs] [-w WIDTH] [FILE]
Wrap input lines in each FILE (standard input by default), writing to standard output
Options:
-b Count bytes rather than columns -s Break at spaces -w Use WIDTH columns instead of 80
free
Display the amount of free and used system memory
freeramdisk DEVICE
Free all memory used by the specified ramdisk
fsck [-ANPRTV] [-C fd] [-t fstype] [fs-options] [filesys...]
Check and repair filesystems
Options:
-A Walk /etc/fstab and check all filesystems -N Don't execute, just show what would be done -P With -A, check filesystems in parallel -R With -A, skip the root filesystem -T Don't show title on startup -V Verbose -C n Write status information to specified filedescriptor -t type List of filesystem types to check
fsck.minix [-larvsmf] /dev/name
Check MINIX filesystem
Options:
-l List all filenames -r Perform interactive repairs -a Perform automatic repairs -v Verbose -s Output superblock information -m Show "mode not cleared" warnings -f Force file system check
fsync [OPTIONS] FILE...Write files' buffered blocks to disk
Options:
-d Avoid syncing metadata
ftpd [-wvS] [-t N] [-T N] [DIR]
Anonymous FTP server
ftpd should be used as an inetd service. ftpd's line for inetd.conf: 21 stream tcp nowait root ftpd ftpd /files/to/serve It also can be ran from tcpsvd:
tcpsvd -vE <IP_ADDRESS> 21 ftpd /files/to/serve
Options:
-w Allow upload -v Log to stderr -S Log to syslog -t,-T Idle and absolute timeouts DIR Change root to this directory
ftpget [OPTIONS] HOST LOCAL_FILE REMOTE_FILE
Retrieve a remote file via FTP
Options:
-c,--continue Continue previous transfer -v,--verbose Verbose -u,--username Username -p,--password Password -P,--port Port number
ftpput [OPTIONS] HOST REMOTE_FILE LOCAL_FILE
Store a local file on a remote machine via FTP
Options:
-v,--verbose Verbose -u,--username Username -p,--password Password -P,--port Port number
fuser [OPTIONS] FILE or PORT/PROTO
Find processes which use FILEs or PORTs
Options:
-m Find processes which use same fs as FILEs -4 Search only IPv4 space -6 Search only IPv6 space -s Silent: just exit with 0 if any processes are found -k Kill found processes (otherwise display PIDs) -SIGNAL Signal to send (default: TERM)
getopt [OPTIONS]
Options:
-a,--alternative Allow long options starting with single - -l,--longoptions=longopts Long options to be recognized -n,--name=progname The name under which errors are reported -o,--options=optstring Short options to be recognized -q,--quiet Disable error reporting by getopt(3) -Q,--quiet-output No normal output -s,--shell=shell Set shell quoting conventions -T,--test Test for getopt(1) version -u,--unquoted Don't quote the output
getty [OPTIONS] BAUD_RATE TTY [TERMTYPE]
Open a tty, prompt for a login name, then invoke /bin/login
Options:
-h Enable hardware (RTS/CTS) flow control -i Do not display /etc/issue before running login -L Local line, do not do carrier detect -m Get baud rate from modem's CONNECT status message -w Wait for a CR or LF before sending /etc/issue -n Do not prompt the user for a login name -f ISSUE_FILE Display ISSUE_FILE instead of /etc/issue -l LOGIN Invoke LOGIN instead of /bin/login -t SEC Terminate after SEC if no username is read -I INITSTR Send INITSTR before anything else -H HOST Log HOST into the utmp file as the hostname
grep [-HhrilLnqvsoweFEABCz] PATTERN [FILE]...
Search for PATTERN in each FILE or standard input
Options:
-H Prefix output lines with filename where match was found -h Suppress the prefixing filename on output -r Recurse -i Ignore case distinctions -l List names of files that match -L List names of files that do not match -n Print line number with output lines -q Quiet. Return 0 if PATTERN is found, 1 otherwise -v Select non-matching lines -s Suppress file open/read error messages -c Only print count of matching lines -o Show only the part of a line that matches PATTERN -m MAX Match up to MAX times per file -w Match whole words only -F PATTERN is a set of newline-separated strings -E PATTERN is an extended regular expression -e PTRN Pattern to match -f FILE Read pattern from file -A Print NUM lines of trailing context -B Print NUM lines of leading context -C Print NUM lines of output context -z Input is NUL terminated
gunzip [OPTIONS] [FILE]...
Uncompress FILEs (or standard input)
Options:
-c Write to standard output -f Force -t Test file integrity
gzip [OPTIONS] [FILE]...
Compress FILEs (or standard input)
Options:
-c Write to standard output -d Decompress -f Force
hd FILE...
hd is an alias for hexdump -C
hdparm [OPTIONS] [DEVICE]
Options:
-a Get/set fs readahead -A Set drive read-lookahead flag (0/1) -b Get/set bus state (0 == off, 1 == on, 2 == tristate) -B Set Advanced Power Management setting (1-255) -c Get/set IDE 32-bit IO setting -C Check IDE power mode status -d Get/set using_dma flag -D Enable/disable drive defect-mgmt -f Flush buffer cache for device on exit -g Display drive geometry -h Display terse usage information -i Display drive identification -I Detailed/current information directly from drive -k Get/set keep_settings_over_reset flag (0/1) -K Set drive keep_features_over_reset flag (0/1) -L Set drive doorlock (0/1) (removable harddisks only) -m Get/set multiple sector count -n Get/set ignore-write-errors flag (0/1) -p Set PIO mode on IDE interface chipset (0,1,2,3,4,...) -P Set drive prefetch count -Q Get/set DMA tagged-queuing depth (if supported) -r Get/set readonly flag (DANGEROUS to set) -R Register an IDE interface (DANGEROUS) -S Set standby (spindown) timeout -t Perform device read timings -T Perform cache read timings -u Get/set unmaskirq flag (0/1) -U Un-register an IDE interface (DANGEROUS) -v Defaults; same as -mcudkrag for IDE drives -V Display program version and exit immediately -w Perform device reset (DANGEROUS) -W Set drive write-caching flag (0/1) (DANGEROUS) -x Tristate device for hotswap (0/1) (DANGEROUS) -X Set IDE xfer mode (DANGEROUS) -y Put IDE drive in standby mode -Y Put IDE drive to sleep -Z Disable Seagate auto-powersaving mode -z Re-read partition table
head [OPTIONS] [FILE]...
Print first 10 lines of each FILE to standard output. With more than one FILE, precede each with a header giving the file name. With no FILE, or when FILE is -, read standard input.
Options:
-n NUM Print first NUM lines instead of first 10 -c NUM Output the first NUM bytes -q Never output headers giving file names -v Always output headers giving file names
hexdump [-bcCdefnosvxR] FILE...
Display file(s) or standard input in a user specified format
Options:
-b One-byte octal display -c One-byte character display -C Canonical hex+ASCII, 16 bytes per line -d Two-byte decimal display -e FORMAT STRING -f FORMAT FILE -n LENGTH Interpret only LENGTH bytes of input -o Two-byte octal display -s OFFSET Skip OFFSET bytes -v Display all input data -x Two-byte hexadecimal display -R Reverse of 'hexdump -Cv'
hostid
Print out a unique 32-bit identifier for the machine
hostname [OPTIONS] [HOSTNAME | -F FILE]
Get or set hostname or DNS domain name
Options:
-s Short -i Addresses for the hostname -d DNS domain name -f Fully qualified domain name -F FILE Use FILE's content as hostname
httpd [-ifv[v]] [-c CONFFILE] [-p [IP:]PORT] [-u USER[:GRP]] [-r REALM] [-h HOME] or httpd -d/-e/-m STRING
Listen for incoming HTTP requests
Options:
-i Inetd mode -f Do not daemonize -v[v] Verbose -c FILE Configuration file (default httpd.conf) -p [IP:]PORT Bind to ip:port (default *:80) -u USER[:GRP] Set uid/gid after binding to port -r REALM Authentication Realm for Basic Authentication -h HOME Home directory (default .) -m STRING MD5 crypt STRING -e STRING HTML encode STRING -d STRING URL decode STRING
hwclock [-r|--show] [-s|--hctosys] [-w|--systohc] [-l|--localtime] [-u|--utc] [-f FILE]
Query and set hardware clock (RTC)
Options:
-r Show hardware clock time -s Set system time from hardware clock -w Set hardware clock to system time -u Hardware clock is in UTC -l Hardware clock is in local time -f FILE Use specified device (e.g. /dev/rtc2)
id [OPTIONS] [USER]
Print information about USER or the current user
Options:
-u Print user ID -g Print group ID -G Print supplementary group IDs -n Print name instead of a number -r Print real user ID instead of effective ID
ifconfig [-a] interface [address]
Configure a network interface
Options:
[add ADDRESS[/PREFIXLEN]] [del ADDRESS[/PREFIXLEN]] [[-]broadcast [ADDRESS]] [[-]pointopoint [ADDRESS]] [netmask ADDRESS] [dstaddr ADDRESS] [outfill NN] [keepalive NN] [hw ether|infiniband ADDRESS] [metric NN] [mtu NN] [[-]trailers] [[-]arp] [[-]allmulti] [multicast] [[-]promisc] [txqueuelen NN] [[-]dynamic] [mem_start NN] [io_addr NN] [irq NN] [up|down] ...
ifdown [-ainmvf] ifaces...
Options:
-a De/configure all interfaces automatically -i FILE Use FILE for interface definitions -n Print out what would happen, but don't do it (note: doesn't disable mappings) -m Don't run any mappings -v Print out what would happen before doing it -f Force de/configuration
ifenslave [-cdf] master-iface <slave-iface...>
Configure network interfaces for parallel routing
Options:
-c, --change-active Change active slave -d, --detach Remove slave interface from bonding device -f, --force Force, even if interface is not Ethernet
ifplugd [OPTIONS]
Network interface plug detection daemon
Options:
-n Do not daemonize -s Do not log to syslog -i IFACE Interface -f/-F Treat link detection error as link down/link up (otherwise exit on error) -a Do not up interface automatically -M Monitor creation/destruction of interface (otherwise it must exist) -r PROG Script to run -x ARG Extra argument for script -I Don't exit on nonzero exit code from script -p Don't run script on daemon startup -q Don't run script on daemon quit -l Run script on startup even if no cable is detected -t SECS Poll time in seconds -u SECS Delay before running script after link up -d SECS Delay after link down -m MODE API mode (mii, priv, ethtool, wlan, auto) -k Kill running daemon
ifup [-ainmvf] ifaces...
Options:
-a De/configure all interfaces automatically -i FILE Use FILE for interface definitions -n Print out what would happen, but don't do it (note: doesn't disable mappings) -m Don't run any mappings -v Print out what would happen before doing it -f Force de/configuration
inetd [-fe] [-q N] [-R N] [CONFFILE]
Listen for network connections and launch programs
Options:
-f Run in foreground -e Log to stderr -q N Socket listen queue (default: 128) -R N Pause services after N connects/min (default: 0 - disabled)
init
Init is the parent of all processes
inotifyd PROG FILE1[:MASK] ...
Run PROG on filesystem changes. When a filesystem event matching MASK occurs on FILEn, PROG <actual_event(s)> <FILEn> [<subfile_name>] is run. Events:
a File is accessed c File is modified e Metadata changed w Writable file is closed 0 Unwritable file is closed r File is opened D File is deleted M File is moved u Backing fs is unmounted o Event queue overflowed x File can't be watched anymore If watching a directory:
m Subfile is moved into dir y Subfile is moved out of dir n Subfile is created d Subfile is deleted
inotifyd waits for PROG to exit. When x event happens for all FILEs, inotifyd exits
insmod [OPTIONS] MODULE [symbol=value]...
Load the specified kernel modules into the kernel
Options:
-f Force module to load into the wrong kernel version -k Make module autoclean-able -v Verbose -q Quiet -L Lock to prevent simultaneous loads of a module -m Output load map to stdout -o NAME Set internal module name to NAME -x Do not export externs
install [-cdDsp] [-o USER] [-g GRP] [-m MODE] [source] dest|directory
Copy files and set attributes
Options:
-c Just copy (default) -d Create directories -D Create leading target directories -s Strip symbol table -p Preserve date -o USER Set ownership -g GRP Set group ownership -m MODE Set permissions
ionice [-c 1-3] [-n 0-7] [-p PID] [PROG]
Change I/O scheduling class and priority
Options:
-c Class. 1:realtime 2:best-effort 3:idle -n Priority
ip [OPTIONS] {address | route | link | tunnel | rule} {COMMAND}
ip [OPTIONS] OBJECT {COMMAND} where OBJECT := {address | route | link | tunnel | rule} OPTIONS := { -f[amily] { inet | inet6 | link } | -o[neline] }
| ipaddr { {add|del} IFADDR dev STRING | {show|flush} | |
| [dev STRING] [to PREFIX] } |
ipaddr {add|delete} IFADDR dev STRING ipaddr {show|flush} [dev STRING] [scope SCOPE-ID] [to PREFIX] [label PATTERN] IFADDR := PREFIX | ADDR peer PREFIX [broadcast ADDR] [anycast ADDR] [label STRING] [scope SCOPE-ID] SCOPE-ID := [host | link | global | NUMBER]
ipcalc [OPTIONS] ADDRESS[[/]NETMASK] [NETMASK]
Calculate IP network settings from a IP address
Options:
-b,--broadcast Display calculated broadcast address -n,--network Display calculated network address -m,--netmask Display default netmask for IP -p,--prefix Display the prefix for IP/NETMASK -h,--hostname Display first resolved host name -s,--silent Don't ever display error messages
ipcrm [-MQS key] [-mqs id]
Upper-case options MQS remove an object by shmkey value. Lower-case options remove an object by shmid value.
Options:
-mM Remove memory segment after last detach -qQ Remove message queue -sS Remove semaphore
ipcs [[-smq] -i shmid] | [[-asmq] [-tcplu]]
-i Show specific resource Resource specification:
-m Shared memory segments -q Message queues -s Semaphore arrays -a All (default) Output format:
-t Time -c Creator -p Pid -l Limits -u Summary
iplink { set DEVICE { up | down | arp { on | off } | show [DEVICE] }
iplink set DEVICE { up | down | arp | multicast { on | off } | dynamic { on | off } | mtu MTU } iplink show [DEVICE]
| iproute { list | flush | { add | del | change | append | | |
| replace | monitor } ROUTE } |
iproute { list | flush } SELECTOR iproute get ADDRESS [from ADDRESS iif STRING] [oif STRING] [tos TOS] iproute { add | del | change | append | replace | monitor } ROUTE SELECTOR := [root PREFIX] [match PREFIX] [proto RTPROTO] ROUTE := [TYPE] PREFIX [tos TOS] [proto RTPROTO] [metric METRIC]
iprule {[list | add | del] RULE}
| iprule [list | add | del] SELECTOR ACTION | |
| SELECTOR := [from PREFIX] [to PREFIX] [tos TOS] [fwmark FWMARK] | |
| [dev STRING] [pref NUMBER] | |
| ACTION := [table TABLE_ID] [nat ADDRESS] | |
| [prohibit | reject | unreachable] | |
| [realms [SRCREALM/]DSTREALM] | |
| TABLE_ID := [local | main | default | NUMBER] |
| iptunnel { add | change | del | show } [NAME] | |
| [mode { ipip | gre | sit }] | |
| [remote ADDR] [local ADDR] [ttl TTL] |
| iptunnel { add | change | del | show } [NAME] | |
| [mode { ipip | gre | sit }] [remote ADDR] [local ADDR] | |
| [[i|o]seq] [[i|o]key KEY] [[i|o]csum] | |
| [ttl TTL] [tos TOS] [[no]pmtudisc] [dev PHYS_DEV] |
kbd_mode [-a|k|s|u] [-C TTY]
Report or set the keyboard mode
Options:
-a Default (ASCII) -k Medium-raw (keyboard) -s Raw (scancode) -u Unicode (utf-8) -C TTY Affect TTY instead of /dev/tty
kill [-l] [-SIG] PID...
Send a signal (default: TERM) to given PIDs
Options:
-l List all signal names and numbers
killall [-l] [-q] [-SIG] process-name...
Send a signal (default: TERM) to given processes
Options:
-l List all signal names and numbers -q Do not complain if no processes were killed
killall5 [-l] [-SIG] [-o PID]...
Send a signal (default: TERM) to all processes outside current session
Options:
-l List all signal names and numbers -o PID Do not signal this PID
klogd [-c N] [-n]
Kernel logger
Options:
-c N Only messages with level < N are printed to console -n Run in foreground
last [-HW] [-f file]
Show listing of the last users that logged into the system
Options:
-W Display with no host column truncation -f file Read from file instead of /var/log/wtmp
length STRING
Print STRING's length
less [-EMNmh~I?] [FILE]...
View a file or list of files. The position within files can be changed, and files can be manipulated in various ways.
Options:
-E Quit once the end of a file is reached -M,-m Display status line with line numbers and percentage through the file -N Prefix line number to each line -I Ignore case in all searches -~ Suppress ~s displayed past the end of the file
ln [OPTIONS] TARGET... LINK|DIRECTORY
Create a link LINK or DIRECTORY/TARGET to the specified TARGET(s)
Options:
-s Make symlinks instead of hardlinks -f Remove existing destination files -n Don't dereference symlinks - treat like normal file -b Make a backup of the target (if exists) before link operation -S suf Use suffix instead of ~ when making backup files
loadfont < font
Load a console font from standard input
loadkmap < keymap
Load a binary keyboard translation table from standard input
logger [OPTIONS] [MESSAGE]
Write MESSAGE to the system log. If MESSAGE is omitted, log stdin.
Options:
-s Log to stderr as well as the system log -t TAG Log using the specified tag (defaults to user name) -p PRIO Priority (numeric or facility.level pair)
login [-p] [-h HOST] [[-f] USER]
Begin a new session on the system
Options:
-f Do not authenticate (user already authenticated) -h Name of the remote host -p Preserve environment
logname
Print the name of the current user
logread [OPTIONS]
Show messages in syslogd's circular buffer
Options:
-f Output data as log grows
| losetup [-o OFS] LOOPDEV FILE - associate loop devices | |
| losetup -d LOOPDEV - disassociate | |
| losetup [-f] - show |
Options:
-o OFS Start OFS bytes into FILE -f Show first free loop device
lpd SPOOLDIR [HELPER [ARGS]]
SPOOLDIR must contain (symlinks to) device nodes or directories with names matching print queue names. In the first case, jobs are sent directly to the device. Otherwise each job is stored in queue directory and HELPER program is called. Name of file to print is passed in $DATAFILE variable. Example:
tcpsvd -E 0 515 softlimit -m 999999 lpd /var/spool ./print
lpq [-P queue[@host[:port]]] [-U USERNAME] [-d JOBID...] [-fs]
Options:
-P lp service to connect to (else uses $PRINTER) -d Delete jobs -f Force any waiting job to be printed -s Short display
lpr -P queue[@host[:port]] -U USERNAME -J TITLE -Vmh [FILE]...
Options:
-P lp service to connect to (else uses $PRINTER) -m Send mail on completion -h Print banner page too -V Verbose
ls [-1AacCdeFilnpLRrSsTtuvwxXhk] [FILE]...
List directory contents
Options:
-1 List in a single column -A Don't list . and .. -a Don't hide entries starting with . -C List by columns -c With -l: sort by ctime --color[={always,never,auto}] Control coloring -d List directory entries instead of contents -e List full date and time -F Append indicator (one of */=@|) to entries -i List inode numbers -l Long listing format -n List numeric UIDs and GIDs instead of names -p Append indicator (one of /=@|) to entries -L List entries pointed to by symlinks -R List subdirectories recursively -r Sort in reverse order -S Sort by file size -s List the size of each file, in blocks -T NUM Assume tabstop every NUM columns -t With -l: sort by modification time -u With -l: sort by access time -v Sort by version -w NUM Assume the terminal is NUM columns wide -x List by lines -X Sort by extension -h List sizes in human readable format (1K 243M 2G)
lsattr [-Radlv] [FILE]...
List file attributes on an ext2 fs
Options:
-R Recursively list subdirectories -a Do not hide entries starting with . -d List directory entries instead of contents -l List long flag names -v List the file's version/generation number
lsmod
List the currently loaded kernel modules
lzmacat FILE
Uncompress to stdout
lzop [-cfvd123456789CF] [FILE]...
-c Write to standard output -f Force -v Verbose -d Decompress -F Don't store or verify checksum -C Also write checksum of compressed block -1..9 Compression level
lzopcat [-vCF] [FILE]...
-v Verbose -F Don't store or verify checksum
makemime [OPTIONS] [FILE]...
Create multipart MIME-encoded message from FILEs
Options:
-o FILE Output. Default: stdout -a HDR Add header. Examples: "From<EMAIL_ADDRESS>"Date: `date -R`" -c CT Content type. Default: text/plain -C CS Charset. Default: us-ascii
Other options are silently ignored
man [OPTIONS] [MANPAGE]...
Format and display manual page
Options:
-a Display all pages -w Show page locations
md5sum [OPTIONS] [FILE]... or: md5sum [OPTIONS] -c [FILE]
Print or check MD5 checksums
Options:
-c Check sums against given list -s Don't output anything, status code shows success -w Warn about improperly formatted checksum lines
mdev [-s]
-s Scan /sys and populate /dev during system boot
It can be run by kernel as a hotplug helper. To activate it: echo /bin/mdev >/proc/sys/kernel/hotplug It uses /etc/mdev.conf with lines [-]DEVNAME UID:GID PERM [>|=PATH] [@|$|*PROG]
mesg [y|n]
| Control write access to your terminal | ||
| y | Allow write access to your terminal | |
| n | Disallow write access to your terminal |
microcom [-d DELAY] [-t TIMEOUT] [-s SPEED] [-X] TTY
Copy bytes for stdin to TTY and from TTY to stdout
Options:
-d Wait up to DELAY ms for TTY output before sending every next byte to it -t Exit if both stdin and TTY are silent for TIMEOUT ms -s Set serial line to SPEED -X Disable special meaning of NUL and Ctrl-X from stdin
mkdir [OPTIONS] DIRECTORY...
Create DIRECTORY
Options:
-m Mode -p No error if exists; make parent directories as needed
mkdosfs [-v] [-n LABEL] FILE_OR_DEVICE [SIZE_IN_KB]
Make a FAT32 filesystem
Options:
-v Verbose -n LBL Volume label
mkfifo [OPTIONS] name
Create named pipe (identical to 'mknod name p')
Options:
-m MODE Mode (default a=rw)
mkfs.minix [-c | -l filename] [-nXX] [-iXX] /dev/name [blocks]
Make a MINIX filesystem
Options:
-c Check device for bad blocks -n [14|30] Maximum length of filenames -i INODES Number of inodes for the filesystem -l FILENAME Read bad blocks list from FILENAME -v Make version 2 filesystem
mkfs.vfat [-v] [-n LABEL] FILE_OR_DEVICE [SIZE_IN_KB]
Make a FAT32 filesystem
Options:
-v Verbose -n LBL Volume label
mknod [OPTIONS] NAME TYPE MAJOR MINOR
Create a special file (block, character, or pipe)
Options:
-m Create the special file using the specified mode (default a=rw) TYPEs include:
b: Make a block device c or u: Make a character device p: Make a named pipe (MAJOR and MINOR are ignored)
mkpasswd [OPTIONS] [PASSWORD] [SALT]
Crypt the PASSWORD using crypt(3)
Options:
-P,--password-fd=NUM Read password from fd NUM -m,--method=TYPE Encryption method TYPE -S,--salt=SALT
mkswap DEVICE
Prepare block device to be used as swap partition
mktemp [-dt] [-p DIR] [TEMPLATE]
Create a temporary file with name based on TEMPLATE and print its name. TEMPLATE must end with XXXXXX (e.g. [/dir/]nameXXXXXX).
Options:
-d Make a directory instead of a file -t Generate a path rooted in temporary directory -p DIR Use DIR as a temporary directory (implies -t)
For -t or -p, directory is chosen as follows: $TMPDIR if set, else -p DIR, else /tmp
modprobe [-knqrsvb] MODULE [symbol=value...]
Options:
-k Make module autoclean-able -n Dry run -q Quiet -r Remove module (stacks) or do autoclean -s Report via syslog instead of stderr -v Verbose -b Apply blacklist to module names too
more [FILE]...
View FILE or standard input one screenful at a time
mount [flags] DEVICE NODE [-o OPT,OPT]
Mount a filesystem. Filesystem autodetection requires /proc.
Options:
-a Mount all filesystems in fstab -f Dry run -i Don't run mount helper -r Read-only mount -w Read-write mount (default) -t FSTYPE Filesystem type -O OPT Mount only filesystems with option OPT (-a only) -o OPT: loop Ignored (loop devices are autodetected) [a]sync Writes are [a]synchronous [no]atime Disable/enable updates to inode access times [no]diratime Disable/enable atime updates to directories [no]relatime Disable/enable atime updates relative to modification time [no]dev (Dis)allow use of special device files [no]exec (Dis)allow use of executable files [no]suid (Dis)allow set-user-id-root programs [r]shared Convert [recursively] to a shared subtree [r]slave Convert [recursively] to a slave subtree [r]private Convert [recursively] to a private subtree [un]bindable Make mount point [un]able to be bind mounted bind Bind a directory to an additional location move Relocate an existing mount point remount Remount a mounted filesystem, changing its flags ro/rw Read-only/read-write mount
There are EVEN MORE flags that are specific to each filesystem You'll have to see the written documentation for those filesystems
mountpoint [-q] <[-dn] DIR | -x DEVICE>
Check if the directory is a mountpoint
Options:
-q Quiet -d Print major/minor device number of the filesystem -n Print device name of the filesystem -x Print major/minor device number of the blockdevice
mt [-f device] opcode value
Control magnetic tape drive operation
Available Opcodes:
bsf bsfm bsr bss datacompression drvbuffer eof eom erase fsf fsfm fsr fss load lock mkpart nop offline ras1 ras2 ras3 reset retension rewind rewoffline seek setblk setdensity setpart tell unload unlock weof wset
mv [OPTIONS] SOURCE DEST or: mv [OPTIONS] SOURCE... DIRECTORY
Rename SOURCE to DEST, or move SOURCE(s) to DIRECTORY
Options:
-f Don't prompt before overwriting -i Interactive, prompt before overwrite
nameif [-s] [-c FILE] [{IFNAME MACADDR}]
Rename network interface while it in the down state
Options:
-c FILE Use configuration file (default: /etc/mactab) -s Use syslog (LOCAL0 facility) IFNAME MACADDR new_interface_name interface_mac_address
nc [OPTIONS] HOST PORT - connect nc [OPTIONS] -l -p PORT [HOST] [PORT] - listen
Options:
-e PROG Run PROG after connect (must be last) -l Listen mode, for inbound connects -n Don't do DNS resolution -s ADDR Local address -p PORT Local port -u UDP mode -v Verbose -w SEC Timeout for connects and final net reads -i SEC Delay interval for lines sent -o FILE Hex dump traffic -z Zero-I/O mode (scanning)
netstat [-laentuwxrWp]
Display networking information
Options:
-l Display listening server sockets -a Display all sockets (default: connected) -e Display other/more information -n Don't resolve names -t Tcp sockets -u Udp sockets -w Raw sockets -x Unix sockets -r Display routing table -W Display with no column truncation -p Display PID/Program name for sockets
nice [-n ADJUST] [PROG [ARGS]]
Run PROG with modified scheduling priority
Options:
-n ADJUST Adjust priority by ADJUST
nmeter format_string
Monitor system in real time
Format specifiers:
%Nc or %[cN] Monitor CPU. N - bar size, default 10 (displays: S:system U:user N:niced D:iowait I:irq i:softirq) %[niface] Monitor network interface 'iface' %m Monitor allocated memory %[mf] Monitor free memory %[mt] Monitor total memory %s Monitor allocated swap %f Monitor number of used file descriptors %Ni Monitor total/specific IRQ rate %x Monitor context switch rate %p Monitor forks %[pn] Monitor # of processes %b Monitor block io %Nt Show time (with N decimal points) %Nd Milliseconds between updates (default:1000) %r Print <cr> instead of <lf> at EOL
nohup PROG [ARGS]
Run PROG immune to hangups, with output to a non-tty
nslookup [HOST] [SERVER]
Query the nameserver for the IP address of the given HOST optionally using a specified DNS server
od [-aBbcDdeFfHhIiLlOovXx] [-t TYPE] [FILE]
Write an unambiguous representation, octal bytes by default, of FILE to standard output. With no FILE or when FILE is -, read standard input.
openvt [-c N] [-sw] [PROG [ARGS]]
Start PROG on a new virtual terminal
Options:
-c N Use specified VT -s Switch to the VT -w Wait for PROG to exit
passwd [OPTIONS] [USER]
Change USER's password. If no USER is specified, changes the password for the current user.
Options:
-a Algorithm to use for password (choices: des, md5) -d Delete password for the account -l Lock (disable) account -u Unlock (re-enable) account
patch [-p NUM] [-i DIFF] [-R] [-N]
-p NUM Strip NUM leading components from file names -i DIFF Read DIFF instead of stdin -R Reverse patch -N Ignore already applied patches
pgrep [-flnovx] [-s SID|-P PPID|PATTERN]
Display process(es) selected by regex PATTERN
Options:
-l Show command name too -f Match against entire command line -n Show the newest process only -o Show the oldest process only -v Negate the match -x Match whole name (not substring) -s Match session ID (0 for current) -P Match parent process ID
pidof [OPTIONS] [NAME...]
List PIDs of all processes with names that match NAMEs
Options:
-s Show only one PID -o PID Omit given pid Use %PPID to omit pid of pidof's parent
ping [OPTIONS] HOST
Send ICMP ECHO_REQUEST packets to network hosts
Options:
-4, -6 Force IPv4 or IPv6 hostname resolution -c CNT Send only CNT pings -s SIZE Send SIZE data bytes in packets (default:56) -I IFACE/IP Use interface or IP address as source -W SEC Seconds to wait for the first response (default:10) (after all -c CNT packets are sent) -w SEC Seconds until ping exits (default:infinite) (can exit earlier with -c CNT) -q Quiet, only displays output at start and when finished
ping6 [OPTIONS] HOST
Send ICMP ECHO_REQUEST packets to network hosts
Options:
-c CNT Send only CNT pings -s SIZE Send SIZE data bytes in packets (default:56) -I IFACE/IP Use interface or IP address as source -q Quiet, only displays output at start and when finished
pivot_root NEW_ROOT PUT_OLD
Move the current root file system to PUT_OLD and make NEW_ROOT the new root file system
pkill [-l|-SIGNAL] [-fnovx] [-s SID|-P PPID|PATTERN]
Send a signal to process(es) selected by regex PATTERN
Options:
-l List all signals -f Match against entire command line -n Signal the newest process only -o Signal the oldest process only -v Negate the match -x Match whole name (not substring) -s Match session ID (0 for current) -P Match parent process ID
popmaildir [OPTIONS] Maildir [connection-helper ...]
Fetch content of remote mailbox to local maildir
Options:
-b Binary mode. Ignored -d Debug. Ignored -m Show used memory. Ignored -V Show version. Ignored -c Use tcpclient. Ignored -a Use APOP protocol. Implied. If server supports APOP -> use it -s Skip authorization -T Get messages with TOP instead with RETR -k Keep retrieved messages on the server -t timeout Network timeout -F "program arg1 arg2 ..." Filter by program. May be multiple -M "program arg1 arg2 ..." Deliver by program -R size Remove old messages on the server >= size (in bytes). Ignored -Z N1-N2 Remove messages from N1 to N2 (dangerous). Ignored -L size Do not retrieve new messages >= size (in bytes). Ignored -H lines Type specified number of lines of a message. Ignored
printenv [VARIABLE...]
Print all or part of environment. If no environment VARIABLE specified, print them all.
printf FORMAT [ARGUMENT...]
Format and print ARGUMENT(s) according to FORMAT, where FORMAT controls the output exactly as in C printf
ps
Report process status
Options:
-o col1,col2=header Select columns for display -T Show threads
pscan [-cb] [-p MIN_PORT] [-P MAX_PORT] [-t TIMEOUT] [-T MIN_RTT] HOST
Scan a host, print all open ports
Options:
-c Show closed ports too -b Show blocked ports too -p Scan from this port (default 1) -P Scan up to this port (default 1024) -t Timeout (default 5000 ms) -T Minimum rtt (default 5 ms, increase for congested hosts)
pwd
Print the full filename of the current working directory
raidautorun DEVICE
Tell the kernel to automatically search and start RAID arrays
rdate [-sp] HOST
Get and possibly set the system date and time from a remote HOST
Options:
-s Set the system date and time (default) -p Print the date and time
rdev
Print the device node associated with the filesystem mounted at '/'
readlink [-fnv] FILE
Display the value of a symlink
Options:
-f Canonicalize by following all symlinks -n Don't add newline -v Verbose
readprofile [OPTIONS]
Options:
-m mapfile (Default: /boot/System.map) -p profile (Default: /proc/profile) -M mult Set the profiling multiplier to mult -i Print only info about the sampling step -v Verbose -a Print all symbols, even if count is 0 -b Print individual histogram-bin counts -s Print individual counters within functions -r Reset all the counters (root only) -n Disable byte order auto-detection
realpath pathname...
Return the absolute pathnames of given argument
reformime [OPTIONS] [FILE]...
Parse MIME-encoded message
Options:
-x prefix Extract content of MIME sections to files -X prog [args] Filter content of MIME sections through prog. Must be the last option
Other options are silently ignored.
renice {{-n INCREMENT} | PRIORITY} [[-p | -g | -u] ID...]
Change priority of running processes
Options:
-n Adjust current nice value (smaller is faster) -p Process id(s) (default) -g Process group id(s) -u Process user name(s) and/or id(s)
reset
Reset the screen
resize
Resize the screen
rm [OPTIONS] FILE...
Remove (unlink) the FILE(s). Use '--' to indicate that all following arguments are non-options.
Options:
-i Always prompt before removing -f Never prompt -r,-R Remove directories recursively
rmdir [OPTIONS] DIRECTORY...
Remove the DIRECTORY, if it is empty
Options:
-p|--parents Include parents --ignore-fail-on-non-empty
rmmod [OPTIONS] [MODULE]...
Unload the specified kernel modules from the kernel
Options:
-w Wait until the module is no longer used -f Force unloading -a Remove all unused modules (recursively)
route [{add|del|delete}]
Edit kernel routing tables
Options:
-n Don't resolve names -e Display other/more information -A inet{6} Select address family
rpm -i -q[ildc]p package.rpm
Manipulate RPM packages
Options:
-i Install package -q Query package -p Query uninstalled package -i Show information -l List contents -d List documents -c List config files
rpm2cpio package.rpm
Output a cpio archive of the rpm file
rtcwake [-a | -l | -u] [-d DEV] [-m MODE] [-s SEC | -t TIME]
Enter a system sleep state until specified wakeup time
-a,--auto Read clock mode from adjtime -l,--local Clock is set to local time -u,--utc Clock is set to UTC time -d,--device=DEV Specify the RTC device -m,--mode=MODE Set the sleep state (default: standby) -s,--seconds=SEC Set the timeout in SEC seconds from now -t,--time=TIME Set the timeout to TIME seconds from epoch
run-parts [-t] [-l] [-a ARG] [-u MASK] DIRECTORY
Run a bunch of scripts in a directory
Options:
-t Print what would be run, but don't actually run anything -a ARG Pass ARG as argument for every program -u MASK Set the umask to MASK before running every program -l Print names of all matching files even if they are not executable
runlevel [utmp]
Find the current and previous system runlevel
If no utmp file exists or if no runlevel record can be found, print "unknown"
runsv dir
Start and monitor a service and optionally an appendant log service
runsvdir [-P] [-s SCRIPT] dir
Start a runsv process for each subdirectory. If it exits, restart it.
-P Put each runsv in a new session -s SCRIPT Run SCRIPT <signo> after signal is processed
rx FILE
Receive a file using the xmodem protocol
script [-afqt] [-c PROG] [OUTFILE]
Options:
-a Append output -c Run PROG, not shell -f Flush output after each write -q Quiet -t Send timing to stderr
scriptreplay timingfile [typescript [divisor]]
Play back typescripts, using timing information
sed [-efinr] SED_CMD [FILE]...
Options:
-e CMD Add CMD to sed commands to be executed -f FILE Add FILE contents to sed commands to be executed -i Edit files in-place -n Suppress automatic printing of pattern space -r Use extended regex syntax
If no -e or -f is given, the first non-option argument is taken as the sed command to interpret. All remaining arguments are names of input files; if no input files are specified, then the standard input is read. Source files will not be modified unless -i option is given.
sendmail [OPTIONS] [RECIPIENT_EMAIL]...
Read email from stdin and send it
Standard options:
-t Read additional recipients from message body -f sender Sender (required) -o options Various options. -oi implied, others are ignored
Busybox specific options:
-w seconds Network timeout -H 'PROG ARGS' Run connection helper Examples: -H 'exec openssl s_client -quiet -tls1 -starttls smtp -connect smtp.gmail.com:25' <email.txt [4<username_and_passwd.txt | -au<username> -ap<password>] -H 'exec openssl s_client -quiet -tls1 -connect smtp.gmail.com:465' <email.txt [4<username_and_passwd.txt | -au<username> -ap<password>] -S server[:port] Server -au<username> Username for AUTH LOGIN -ap<password> Password for AUTH LOGIN -am<method> Authentication method. Ignored. LOGIN is implied
Other options are silently ignored; -oi -t is implied Use makemime applet to create message with attachments
seq [-w] [-s SEP] [FIRST [INC]] LAST
Print numbers from FIRST to LAST, in steps of INC. FIRST, INC default to 1
Options:
-w Pad to last with leading zeros -s SEP String separator
setarch personality program [args...]
Personality may be:
linux32 Set 32bit uname emulation linux64 Set 64bit uname emulation
setconsole [-r|--reset] [DEVICE]
Redirect system console output to DEVICE (default: /dev/tty)
Options:
-r Reset output to /dev/console
setfont FONT [-m MAPFILE] [-C TTY]
Load a console font
Options:
-m MAPFILE Load console screen map -C TTY Affect TTY instead of /dev/tty
setkeycodes SCANCODE KEYCODE...
Set entries into the kernel's scancode-to-keycode map, allowing unusual keyboards to generate usable keycodes.
SCANCODE may be either xx or e0xx (hexadecimal), and KEYCODE is given in decimal
setlogcons N
Redirect the kernel output to console N (0 for current)
setsid PROG [ARG...]
Run PROG in a new session. PROG will have no controlling terminal
and will not be affected by keyboard signals (Ctrl-C etc).
See setsid(2)
for details.
setuidgid account prog args
Set uid and gid to account's uid and gid, removing all supplementary groups and run PROG
sha1sum [OPTIONS] [FILE]... or: sha1sum [OPTIONS] -c [FILE]
Print or check SHA1 checksums
Options:
-c Check sums against given list -s Don't output anything, status code shows success -w Warn about improperly formatted checksum lines
sha256sum [OPTIONS] [FILE]... or: sha256sum [OPTIONS] -c [FILE]
Print or check SHA256 checksums
Options:
-c Check sums against given list -s Don't output anything, status code shows success -w Warn about improperly formatted checksum lines
sha512sum [OPTIONS] [FILE]... or: sha512sum [OPTIONS] -c [FILE]
Print or check SHA512 checksums
Options:
-c Check sums against given list -s Don't output anything, status code shows success -w Warn about improperly formatted checksum lines
showkey [-a | -k | -s]
Show keys pressed
Options:
-a Display decimal/octal/hex values of the keys -k Display interpreted keycodes (default) -s Display raw scan-codes
slattach [-cehmLF] [-s SPEED] [-p PROTOCOL] DEVICE
Attach network interface(s) to serial line(s)
Options:
-p PROT Set protocol (slip, cslip, slip6, clisp6 or adaptive) -s SPD Set line speed -e Exit after initializing device -h Exit when the carrier is lost -c PROG Run PROG when the line is hung up -m Do NOT initialize the line in raw 8 bits mode -L Enable 3-wire operation -F Disable RTS/CTS flow control
sleep [N]...
Pause for a time equal to the total of the args given, where each arg can have an optional suffix of (s)econds, (m)inutes, (h)ours, or (d)ays
| softlimit [-a BYTES] [-m BYTES] [-d BYTES] [-s BYTES] [-l BYTES] | |
| [-f BYTES] [-c BYTES] [-r BYTES] [-o N] [-p N] [-t N] | |
| PROG ARGS |
Set soft resource limits, then run PROG
Options:
-a BYTES Limit total size of all segments -m BYTES Same as -d BYTES -s BYTES -l BYTES -a BYTES -d BYTES Limit data segment -s BYTES Limit stack segment -l BYTES Limit locked memory size -o N Limit number of open files per process -p N Limit number of processes per uid Options controlling file sizes:
-f BYTES Limit output file sizes -c BYTES Limit core file size Efficiency opts:
-r BYTES Limit resident set size -t N Limit CPU time, process receives a SIGXCPU after N seconds
sort [-nrugMcszbdfimSTokt] [-o FILE] [-k start[.offset][opts][,end[.offset][opts]] [-t CHAR] [FILE]...
Sort lines of text
Options:
-b Ignore leading blanks -c Check whether input is sorted -d Dictionary order (blank or alphanumeric only) -f Ignore case -g General numerical sort -i Ignore unprintable characters -k Sort key -M Sort month -n Sort numbers -o Output to file -k Sort by key -t CHAR Key separator -r Reverse sort order -s Stable (don't sort ties alphabetically) -u Suppress duplicate lines -z Lines are terminated by NUL, not newline -mST Ignored for GNU compatibility
split [OPTIONS] [INPUT [PREFIX]]
Options:
-b n[k|m] Split by bytes -l n Split by lines -a n Use n letters as suffix
start-stop-daemon [OPTIONS] [-S|-K] ... [-- arguments...]
Search for matching processes, and then -K: stop all matching processes. -S: start a process unless a matching process is found.
Process matching:
-u,--user USERNAME|UID Match only this user's processes -n,--name NAME Match processes with NAME in comm field in /proc/PID/stat -x,--exec EXECUTABLE Match processes with this command in /proc/PID/cmdline -p,--pidfile FILE Match a process with PID from the file All specified conditions must match -S only: -x,--exec EXECUTABLE Program to run -a,--startas NAME Zeroth argument -b,--background Background -N,--nicelevel N Change nice level -c,--chuid USER[:[GRP]] Change to user/group -m,--make-pidfile Write PID to the pidfile specified by -p -K only: -s,--signal SIG Signal to send -t,--test Match only, exit with 0 if a process is found Other:
-o,--oknodo Exit with status 0 if nothing is done -v,--verbose Verbose -q,--quiet Quiet
stat [OPTIONS] FILE...
Display file (default) or filesystem status
Options:
-c fmt Use the specified format -f Display filesystem status -L Dereference links -t Display info in terse form
Valid format sequences for files:
%a Access rights in octal %A Access rights in human readable form %b Number of blocks allocated (see %B) %B The size in bytes of each block reported by %b %d Device number in decimal %D Device number in hex %f Raw mode in hex %F File type %g Group ID of owner %G Group name of owner %h Number of hard links %i Inode number %n File name %N Quoted file name with dereference if symlink %o I/O block size %s Total size, in bytes %t Major device type in hex %T Minor device type in hex %u User ID of owner %U User name of owner %x Time of last access %X Time of last access as seconds since Epoch %y Time of last modification %Y Time of last modification as seconds since Epoch %z Time of last change %Z Time of last change as seconds since Epoch
Valid format sequences for file systems:
%a Free blocks available to non-superuser %b Total data blocks in file system %c Total file nodes in file system %d Free file nodes in file system %f Free blocks in file system %i File System ID in hex %l Maximum length of filenames %n File name %s Block size (for faster transfer) %S Fundamental block size (for block counts) %t Type in hex %T Type in human readable form
strings [-afo] [-n LEN] [FILE]...
Display printable strings in a binary file
Options:
-a Scan whole file (default) -f Precede strings with filenames -n LEN At least LEN characters form a string (default 4) -o Precede strings with decimal offsets
stty [-a|g] [-F DEVICE] [SETTING]...
Without arguments, prints baud rate, line discipline, and deviations from stty sane
Options:
-F DEVICE Open device instead of stdin -a Print all current settings in human-readable form -g Print in stty-readable form [SETTING] See manpage
su [OPTIONS] [-] [username]
Change user id or become root
Options:
-p, -m Preserve environment -c CMD Command to pass to 'sh -c' -s SH Shell to use instead of default shell
sulogin [OPTIONS] [TTY]
Single user login
Options:
-t N Timeout
sum [-rs] [FILE]...

Control services monitored by runsv supervisor. Commands (only first character is enough):
status: query service status up: if service isn't running, start it. If service stops, restart it once: like 'up', but if service stops, don't restart it down: send TERM and CONT signals. If ./run exits, start ./finish if it exists. After it stops, do not restart service exit: send TERM and CONT signals to service and log service. If they exit, runsv exits too pause, cont, hup, alarm, interrupt, quit, 1, 2, term, kill: send STOP, CONT, HUP, ALRM, INT, QUIT, USR1, USR2, TERM, KILL signal to service
svlogd [-ttv] [-r c] [-R abc] [-l len] [-b buflen] dir...
Continuously read log data from standard input, optionally filter log messages, and write the data to one or more automatically rotated logs
swapoff [-a] [DEVICE]
Stop swapping on DEVICE
Options:
-a Stop swapping on all swap devices
swapon [-a] [-p pri] [DEVICE]
Start swapping on DEVICE
Options:
-a Start swapping on all swap devices -p pri Set swap device priority
switch_root [-c /dev/console] NEW_ROOT NEW_INIT [ARGS]
Free initramfs and switch to another root fs:
chroot to NEW_ROOT, delete all in /, move NEW_ROOT to /, execute NEW_INIT. PID must be 1. NEW_ROOT must be a mountpoint.
Options:
-c DEV Reopen stdio to DEV after switch
sync
Write all buffered blocks to disk
sysctl [OPTIONS] [VALUE]...
Configure kernel parameters at runtime
Options:
-n Don't print key names -e Don't warn about unknown keys -w Change sysctl setting -p FILE Load sysctl settings from FILE (default /etc/sysctl.conf) -a Display all values -A Display all values in table form
syslogd [OPTIONS]
System logging utility. Note that this version of syslogd ignores /etc/syslog.conf.
Options:
-n Run in foreground -O FILE Log to given file (default:/var/log/messages) -l n Set local log level -S Smaller logging output -s SIZE Max size (KB) before rotate (default:200KB, 0=off) -b NUM Number of rotated logs to keep (default:1, max=99, 0=purge) -R HOST[:PORT] Log to IP or hostname on PORT (default PORT=514/UDP) -L Log locally and via network (default is network only if -R) -D Drop duplicates -C[size(KiB)] Log to shared mem buffer (read it using logread)
tac [FILE]...
Concatenate FILE(s) and print them in reverse
tail [OPTIONS] [FILE]...
Print last 10 lines of each FILE to standard output. With more than one FILE, precede each with a header giving the file name. With no FILE, or when FILE is -, read standard input.
Options:
-c N[kbm] Output the last N bytes -n N[kbm] Print last N lines instead of last 10 -f Output data as the file grows -q Never output headers giving file names -s SEC Wait SEC seconds between reads with -f -v Always output headers giving file names
If the first character of N (bytes or lines) is a '+', output begins with the Nth item from the start of each file, otherwise, print the last N items in the file. N bytes may be suffixed by k (x1024), b (x512), or m (1024^2).
tar -[czjaZxtvO] [-X FILE] [-f TARFILE] [-C DIR] [FILE(s)]...
Create, extract, or list files from a tar file
Options:
c Create x Extract t List Archive format selection:
z Filter the archive through gzip j Filter the archive through bzip2 a Filter the archive through lzma Z Filter the archive through compress File selection:
f Name of TARFILE or "-" for stdin O Extract to stdout exclude File to exclude X File with names to exclude C Change to directory DIR before operation v Verbose
taskset [-p] [MASK] [PID | PROG [ARGS]]
Set or get CPU affinity
Options:
-p Operate on an existing PID
tcpsvd [-hEv] [-c N] [-C N[:MSG]] [-b N] [-u USER] [-l NAME] IP PORT PROG
Create TCP socket, bind to IP:PORT and listen for incoming connection. Run PROG for each connection.
IP IP to listen on. '0' = all PORT Port to listen on PROG [ARGS] Program to run -l NAME Local hostname (else looks up local hostname in DNS) -u USER[:GRP] Change to user/group after bind -c N Handle up to N connections simultaneously -b N Allow a backlog of approximately N TCP SYNs -C N[:MSG] Allow only up to N connections from the same IP New connections from this IP address are closed immediately. MSG is written to the peer before close -h Look up peer's hostname -E Do not set up environment variables -v Verbose
tee [OPTIONS] [FILE]...
Copy standard input to each FILE, and also to standard output
Options:
-a Append to the given FILEs, do not overwrite -i Ignore interrupt signals (SIGINT)
telnet [-a] [-l USER] HOST [PORT]
Connect to telnet server
Options:
-a Automatic login with $USER variable -l USER Automatic login as USER
telnetd [OPTIONS]
Handle incoming telnet connections
Options:
-l LOGIN Exec LOGIN on connect -f ISSUE_FILE Display ISSUE_FILE instead of /etc/issue -K Close connection as soon as login exits (normally wait until all programs close slave pty) -p PORT Port to listen on -b ADDR[:PORT] Address to bind to -F Run in foreground -i Run as inetd service -w SEC Run as inetd service in wait mode, linger time SEC -S Log to syslog (implied by -i or without -F and -w)
test EXPRESSION ]
Check file types, compare values etc. Return a 0/1 exit code depending on logical value of EXPRESSION
tftp [OPTIONS] HOST [PORT]
Transfer a file from/to tftp server
Options:
-l FILE Local FILE -r FILE Remote FILE -g Get file -p Put file -b SIZE Transfer blocks of SIZE octets
tftpd [-cr] [-u USER] [DIR]
Transfer a file on tftp client's request
tftpd should be used as an inetd service. tftpd's line for inetd.conf: 69 dgram udp nowait root tftpd tftpd /files/to/serve It also can be ran from udpsvd:
udpsvd -vE <IP_ADDRESS> 69 tftpd /files/to/serve
Options:
-r Prohibit upload -c Allow file creation via upload -u Access files as USER
time [OPTIONS] PROG [ARGS]
Run PROG. When it finishes, its resource usage is displayed.
Options:
-v Verbose
timeout [-t SECS] [-s SIG] PROG [ARGS]
Runs PROG. Sends SIG to it if it is not gone in SECS seconds. Defaults: SECS: 10, SIG: TERM.
top [-b] [-nCOUNT] [-dSECONDS] [-m]
Provide a view of process activity in real time. Read the status of all processes from /proc each SECONDS and show the status for however many processes will fit on the screen.
touch [-c] [-d DATE] FILE [FILE]...
Update the last-modified date on the given FILE[s]
Options:
-c Do not create files -d DT Date/time to use
tr [-cds] STRING1 [STRING2]
Translate, squeeze, and/or delete characters from standard input, writing to standard output
Options:
-c Take complement of STRING1 -d Delete input characters coded STRING1 -s Squeeze multiple output characters of STRING2 into one character
| traceroute [-FIldnrv] [-f 1st_ttl] [-m max_ttl] [-p port#] [-q nqueries] | |
| [-s src_addr] [-t tos] [-w wait] [-g gateway] [-i iface] | |
| [-z pausemsecs] HOST [data size] |
Trace the route to HOST
Options:
-F Set the don't fragment bit -I Use ICMP ECHO instead of UDP datagrams -l Display the ttl value of the returned packet -d Set SO_DEBUG options to socket -n Print hop addresses numerically rather than symbolically -r Bypass the normal routing tables and send directly to a host -v Verbose -m max_ttl Max time-to-live (max number of hops) -p port# Base UDP port number used in probes (default 33434) -q nqueries Number of probes per 'ttl' (default 3) -s src_addr IP address to use as the source address -t tos Type-of-service in probe packets (default 0) -w wait Time in seconds to wait for a response (default 3 sec) -g Loose source route gateway (8 max)
true
Return an exit code of TRUE (0)
tty
Print file name of standard input's terminal
Options:
-s Print nothing, only return exit status
ttysize [w] [h]
Print dimension(s) of standard input's terminal, on error return 80x25
| udhcpc [-Cfbnqtvo] [-c CID] [-V VCLS] [-H HOSTNAME] [-i INTERFACE] | |
| [-p pidfile] [-r IP] [-s script] [-O dhcp-option]... |
-V,--vendorclass=CLASSID Vendor class identifier -i,--interface=INTERFACE Interface to use (default eth0) -H,-h,--hostname=HOSTNAME Client hostname -c,--clientid=CLIENTID Client identifier -C,--clientid-none Suppress default client identifier -p,--pidfile=file Create pidfile -r,--request=IP IP address to request -s,--script=file Run file at DHCP events (default /usr/share/udhcpc/default.script) -t,--retries=N Send up to N request packets -T,--timeout=N Try to get a lease for N seconds (default 3) -A,--tryagain=N Wait N seconds (default 20) after failure -O,--request-option=OPT Request DHCP option OPT (cumulative) -o,--no-default-options Do not request any options (unless -O is also given) -f,--foreground Run in foreground -b,--background Background if lease is not immediately obtained -S,--syslog Log to syslog too -n,--now Exit with failure if lease is not immediately obtained -q,--quit Quit after obtaining lease -R,--release Release IP on quit -a,--arping Use arping to validate offered address
udhcpd [-fS] [configfile]
DHCP server
-f Run in foreground -S Log to syslog too
udpsvd [-hEv] [-c N] [-u USER] [-l NAME] IP PORT PROG
Create UDP socket, bind to IP:PORT and wait for incoming packets. Run PROG for each packet, redirecting all further packets with same peer ip:port to it.
IP IP to listen on. '0' = all PORT Port to listen on PROG [ARGS] Program to run -l NAME Local hostname (else looks up local hostname in DNS) -u USER[:GRP] Change to user/group after bind -c N Handle up to N connections simultaneously -h Look up peer's hostname -E Do not set up environment variables -v Verbose
umount [flags] FILESYSTEM|DIRECTORY
Unmount file systems
Options:
-a Unmount all file systems -r Try to remount devices as read-only if mount is busy -l Lazy umount (detach filesystem) -f Force umount (i.e., unreachable NFS server) -d Free loop device if it has been used
uname [-amnrspv]
Print system information
Options:
-a Print all -m The machine (hardware) type -n Hostname -r OS release -s OS name (default) -p Processor type -v OS version
uncompress [-c] [-f] [name...]
Uncompress .Z file[s]
Options:
-c Extract to stdout -f Overwrite an existing file
unexpand [-f][-a][-t NUM] [FILE|-]
Convert spaces to tabs, writing to standard output
Options:
-a,--all Convert all blanks -f,--first-only Convert only leading blanks -t,--tabs=N Tabstops every N chars
uniq [-fscduw]... [INPUT [OUTPUT]]
Discard duplicate lines
Options:
-c Prefix lines by the number of occurrences -d Only print duplicate lines -u Only print unique lines -f N Skip first N fields -s N Skip first N chars (after any skipped fields) -w N Compare N characters in line
unix2dos [OPTION] [FILE]
Convert FILE in-place from Unix to DOS format. When no file is given, use stdin/stdout.
Options:
-u dos2unix -d unix2dos
unlzma [OPTIONS] [FILE]
Uncompress FILE (or standard input if FILE is '-' or omitted)
Options:
-c Write to standard output -f Force
unlzop [-cfvCF] [FILE]...
-c Write to standard output -f Force -v Verbose -F Don't store or verify checksum
unzip [-opts[modifiers]] file[.zip] [list] [-x xlist] [-d exdir]
Extract files from ZIP archives
Options:
-l List archive contents (with -q for short form) -n Never overwrite existing files (default) -o Overwrite files without prompting -p Send output to stdout -q Quiet -x Exclude these files -d Extract files into this directory
uptime
Display the time since the last boot
usleep N
Pause for N microseconds
uudecode [-o outfile] [infile]
Uudecode a file Finds outfile name in uuencoded source unless -o is given
uuencode [-m] [infile] stored_filename
Uuencode a file to stdout
Options:
-m Use base64 encoding per RFC1521
vconfig COMMAND [OPTIONS]
Create and remove virtual ethernet devices
Options:
add [interface-name] [vlan_id] rem [vlan-name] set_flag [interface-name] [flag-num] [0 | 1] set_egress_map [vlan-name] [skb_priority] [vlan_qos] set_ingress_map [vlan-name] [skb_priority] [vlan_qos] set_name_type [name-type]
vi [OPTIONS] [FILE]...
Edit FILE
Options:
-c Initial command to run ($EXINIT also available) -R Read-only - do not write to the file -H Short help regarding available features
vlock [OPTIONS]
Lock a virtual terminal. A password is required to unlock.
Options:
-a Lock all VTs
volname [DEVICE]
Show CD volume name of the DEVICE (default /dev/cdrom)
watch [-n seconds] [-t] PROG [ARGS]
Run PROG periodically
Options:
-n Loop period in seconds (default 2) -t Don't print header
watchdog [-t N[ms]] [-T N[ms]] [-F] DEV
Periodically write to watchdog device DEV
Options:
-T N Reboot after N seconds if not reset (default 60) -t N Reset every N seconds (default 30) -F Run in foreground
Use 500ms to specify period in milliseconds
wc [OPTIONS] [FILE]...
Print line, word, and byte counts for each FILE, and a total line if more than one FILE is specified. With no FILE, read standard input.
Options:
-c Print the byte counts -l Print the newline counts -L Print the length of the longest line -w Print the word counts
| wget [-c|--continue] [-s|--spider] [-q|--quiet] [-O|--output-document file] | |
| [--header 'header: value'] [-Y|--proxy on/off] [-P DIR] | |
| [-U|--user-agent agent] url |
Retrieve files via HTTP or FTP
Options:
-s Spider mode - only check file existence -c Continue retrieval of aborted transfer -q Quiet -P Set directory prefix to DIR -O Save to filename ('-' for stdout) -U Adjust 'User-Agent' field -Y Use proxy ('on' or 'off')
which [COMMAND]...
Locate a COMMAND
who [-a]
Show who is logged on
Options:
-a show all
whoami
Print the user name associated with the current effective user id
xargs [OPTIONS] [PROG [ARGS]]
Run PROG on every item given by standard input
Options:
-p Ask user whether to run each command -r Do not run command if input is empty -0 Input is separated by NUL characters -t Print the command on stderr before execution -e[STR] STR stops input processing -n N Pass no more than N args to PROG -s N Pass command line of no more than N bytes -x Exit if size is exceeded
yes [OPTIONS] [STRING]
Repeatedly output a line with STRING, or 'y'
zcat FILE
Uncompress to stdout
zcip [OPTIONS] IFACE SCRIPT
Manage a ZeroConf IPv4 link-local address
Options:
-f Run in foreground -q Quit after obtaining address -r 169.254.x.x Request this address first -v Verbose
With no -q, runs continuously monitoring for ARP conflicts, exits only on I/O errors (link down etc)
GNU Libc (glibc) uses the Name Service Switch (NSS) to configure the behavior of the C library for the local environment, and to configure how it reads system data, such as passwords and group information. This is implemented using an /etc/nsswitch.conf configuration file, and using one or more of the /lib/libnss_* libraries. BusyBox tries to avoid using any libc calls that make use of NSS. Some applets however, such as login and su, will use libc functions that require NSS.
If you enable CONFIG_USE_BB_PWD_GRP, BusyBox will use internal functions to directly access the /etc/passwd, /etc/group, and /etc/shadow files without using NSS. This may allow you to run your system without the need for installing any of the NSS configuration files and libraries.
When used with glibc, the BusyBox 'networking' applets will similarly require that you install at least some of the glibc NSS stuff (in particular, /etc/nsswitch.conf, /lib/libnss_dns*, /lib/libnss_files*, and /lib/libresolv*).
Shameless Plug: As an alternative, one could use a C library such as uClibc. In addition to making your system significantly smaller, uClibc does not require the use of any NSS support files or libraries.
Denis Vlasenko<EMAIL_ADDRESS>The following people have contributed code to BusyBox whether they know it or not. If you have written code included in BusyBox, you should probably be listed here so you can obtain your bit of eternal glory. If you should be listed here, or the description of what you have done needs more detail, or is incorrect, please send in an update.
Emanuele Aina<EMAIL_ADDRESS>run-parts
Erik Andersen<EMAIL_ADDRESS>Tons of new stuff, major rewrite of most of the core apps, tons of new apps as noted in header files. Lots of tedious effort writing these boring docs that nobody is going to actually read.
Laurence Anderson<EMAIL_ADDRESS>rpm2cpio, unzip, get_header_cpio, read_gz interface, rpm
Jeff Angielski<EMAIL_ADDRESS>ftpput, ftpget
Edward Betts<EMAIL_ADDRESS>expr, hostid, logname, whoami
John Beppu<EMAIL_ADDRESS>du, nslookup, sort
Brian Candler<EMAIL_ADDRESS>tiny-ls(ls)
Randolph Chung<EMAIL_ADDRESS>fbset, ping, hostname
Dave Cinege<EMAIL_ADDRESS>more(v2), makedevs, dutmp, modularization, auto links file, various fixes, Linux Router Project maintenance
Jordan Crouse<EMAIL_ADDRESS>ipcalc
Magnus Damm<EMAIL_ADDRESS>tftp client insmod powerpc support
Larry Doolittle<EMAIL_ADDRESS>pristine source directory compilation, lots of patches and fixes.
Glenn Engel<EMAIL_ADDRESS>httpd
Gennady Feldman<EMAIL_ADDRESS>Sysklogd (single threaded syslogd, IPC Circular buffer support, logread), various fixes.
Karl M. Hegbloom<EMAIL_ADDRESS>cp_mv.c, the test suite, various fixes to utility.c, &c.
Daniel Jacobowitz<EMAIL_ADDRESS>mktemp.c
Matt Kraai<EMAIL_ADDRESS>documentation, bugfixes, test suite
Stephan Linz<EMAIL_ADDRESS>ipcalc, Red Hat equivalence
John Lombardo<EMAIL_ADDRESS>tr
Glenn McGrath<EMAIL_ADDRESS>Common unarchiving code and unarchiving applets, ifupdown, ftpgetput, nameif, sed, patch, fold, install, uudecode. Various bugfixes, review and apply numerous patches.
Manuel Novoa III<EMAIL_ADDRESS>cat, head, mkfifo, mknod, rmdir, sleep, tee, tty, uniq, usleep, wc, yes, mesg, vconfig, make_directory, parse_mode, dirname, mode_string, get_last_path_component, simplify_path, and a number trivial libbb routines
also bug fixes, partial rewrites, and size optimizations in ash, basename, cal, cmp, cp, df, du, echo, env, ln, logname, md5sum, mkdir, mv, realpath, rm, sort, tail, touch, uname, watch, arith, human_readable, interface, dutmp, ifconfig, route
Vladimir Oleynik<EMAIL_ADDRESS>cmdedit; xargs(current), httpd(current); ports: ash, crond, fdisk, inetd, stty, traceroute, top; locale, various fixes and irreconcilable critic of everything not perfect.
Bruce Perens<EMAIL_ADDRESS>Original author of BusyBox in 1995, 1996. Some of his code can still be found hiding here and there...
Tim Riker<EMAIL_ADDRESS>bug fixes, member of fan club
Kent Robotti<EMAIL_ADDRESS>reset, tons and tons of bug reports and patches.
Chip Rosenthal<EMAIL_ADDRESS><EMAIL_ADDRESS>wget - Contributed by permission of Covad Communications
Pavel Roskin<EMAIL_ADDRESS>Lots of bugs fixes and patches.
Gyepi Sam<EMAIL_ADDRESS>Remote logging feature for syslogd
Linus Torvalds<EMAIL_ADDRESS>mkswap, fsck.minix, mkfs.minix
Mark Whitley<EMAIL_ADDRESS>grep, sed, cut, xargs(previous), style-guide, new-applet-HOWTO, bug fixes, etc.
Charles P. Wright<EMAIL_ADDRESS>gzip, mini-netcat(nc)
Enrique Zanardi<EMAIL_ADDRESS>tarcat (since removed), loadkmap, various fixes, Debian maintenance
Tito Ragusa<EMAIL_ADDRESS>devfsd and size optimizations in strings, openvt and deallocvt.


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| LSM-Leisure and Sports Mgt |
| NR |
15849 |
LSM |
5120 |
001 |
24M |
3.000 |
Community Development through Leisure, Sport and Tourism |
MW |
12:40 pm-02:05 pm |
5 |
1 |
4 |
33 |
14 |
19 |
John Randall Dunlap (P) |
01/17-05/04 |
AMG 210 |
Credit from 4-Year College and Upper-Division Work |
| C |
14480 |
LSM |
5380 |
D01 |
24M |
3.000 |
(EXL) Disabilities and Diversity in Leisure, Sport & Tourism |
|
TBA |
11 |
11 |
0 |
0 |
0 |
0 |
Victoria Dawn Shelar (P) |
01/17-05/04 |
TBA TBA |
Distance Learning and Experiential Learning and Gerontology Grad Cert and Distance Education Fee-GR and Credit from 4-Year College and Upper-Division Work |
| C |
14481 |
LSM |
5540 |
D01 |
24M |
3.000 |
(EXL) Organization & Administration of Leisure, Sport & Tourism |
|
TBA |
11 |
11 |
0 |
0 |
0 |
0 |
Victoria Dawn Shelar (P) |
01/17-05/04 |
TBA TBA |
Distance Learning and Experiential Learning and Distance Education Fee-GR and Credit from 4-Year College and Upper-Division Work |
| NR |
17577 |
LSM |
5580 |
001 |
24M |
3.000 |
Seminar Outdoor Rec and Environmental Issues |
TR |
08:00 am-09:25 am |
5 |
2 |
3 |
20 |
9 |
11 |
John Randall Dunlap (P) |
01/17-05/04 |
MC 100A |
Credit from 4-Year College and Upper-Division Work |
| NR |
14497 |
LSM |
6640 |
001 |
24M |
3.000 |
Thesis Research |
|
TBA |
2 |
1 |
1 |
0 |
0 |
0 |
Helen J Gray (P) |
01/17-05/04 |
TBA TBA |
|
| C |
14660 |
LSM |
6640 |
003 |
24M |
1.000 |
Thesis Research |
|
TBA |
2 |
2 |
0 |
0 |
0 |
0 |
Helen J Gray (P) |
01/17-05/04 |
TBA TBA |
|
| NR |
14661 |
LSM |
6640 |
004 |
24M |
3.000 |
Thesis Research |
|
TBA |
2 |
1 |
1 |
0 |
0 |
0 |
John Randall Dunlap (P) |
01/17-05/04 |
TBA TBA |
|
| NR |
17479 |
LSM |
6640 |
006 |
24M |
3.000 |
Thesis Research |
|
TBA |
3 |
1 |
2 |
0 |
0 |
0 |
Steven G Estes (P) |
01/17-05/04 |
TBA TBA |
|
| C |
16491 |
LSM |
6670 |
001 |
24M |
3.000 |
Behavioral Concepts in Leisure and Sport |
TR |
11:20 am-12:45 pm |
10 |
11 |
-1 |
14 |
14 |
0 |
Steven G Estes (P) |
01/17-05/04 |
AMG 204 |
Credit from 4-Year College and Upper-Division Work |
| NR |
17168 |
LSM |
6850 |
S01 |
24M |
3.000 |
(STUDY ABROAD) Cross-Cultural Perspectives in Leisure & Tourism: Mendoza, Argentina |
|
TBA |
10 |
3 |
7 |
0 |
0 |
0 |
Tony V Johnston (P) |
01/17-05/04 |
TBA TBA |
Study Abroad and Credit from 4-Year College and Upper-Division Work |
| C |
12275 |
LSM |
6880 |
001 |
24M |
3.000 |
Internship/Special Project |
|
TBA |
1 |
3 |
-2 |
0 |
0 |
0 |
Steven G Estes (P) |
01/17-05/04 |
TBA TBA |
Credit from 4-Year College and Upper-Division Work |
| C |
14733 |
LSM |
6880 |
002 |
24M |
3.000 |
Internship/Special Project |
|
TBA |
2 |
2 |
0 |
0 |
0 |
0 |
Helen J Gray (P) |
01/17-05/04 |
TBA TBA |
Credit from 4-Year College and Upper-Division Work |
| C |
14929 |
LSM |
6910 |
001 |
24M |
3.000 |
Special Problems |
|
TBA |
1 |
1 |
0 |
0 |
0 |
0 |
Helen J Gray (P) |
01/17-05/04 |
TBA TBA |
Credit from 4-Year College and Upper-Division Work |
| C |
16490 |
LSM |
7670 |
001 |
24M |
3.000 |
Behavioral Concepts in Leisure and Sport |
TR |
11:20 am-12:45 pm |
3 |
3 |
0 |
14 |
14 |
0 |
Steven G Estes (P) |
01/17-05/04 |
AMG 204 |
|


|
|
Boost.RegexStandards Conformance |
|
Boost.regex is intended to conform to the regular expression standardization proposal, which will appear in a future C++ standard technical report (and hopefully in a future version of the standard). Currently there are some differences in how the regular expression traits classes are defined, these will be fixed in a future release.
All of the ECMAScript regular expression syntax features are supported, except that:
Negated class escapes (\S, \D and \W) are not permitted inside character class definitions ( [...] ).
The escape sequence \u matches any upper case character (the same as [[:upper:]]) rather than a Unicode escape sequence; use \x{DDDD} for Unicode escape sequences.
Almost all Perl features are supported, except for:
\N{name} Use [[:name:]] instead.
\pP and \PP
(?imsx-imsx)
(?<=pattern)
(?<!pattern)
(?{code})
(??{code})
(?(condition)yes-pattern) and (?(condition)yes-pattern|no-pattern)
These embarrassments / limitations will be removed in due course, mainly dependent upon user demand.
All the POSIX basic and extended regular expression features are supported, except that:
No character collating names are recognized except those specified in the POSIX standard for the C locale, unless they are explicitly registered with the traits class.
Character equivalence classes ( [[=a=]] etc) are probably buggy except on Win32. Implementing this feature requires knowledge of the format of the string sort keys produced by the system; if you need this, and the default implementation doesn't work on your platform, then you will need to supply a custom traits class.
Revised 24 Oct 2003
© Copyright John Maddock 1998- 2003
Use, modification and distribution are subject to the Boost Software License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)


Algorithms Index
The Congugate is a unit which takes in a complex number (either a ComplexSpectrum or a ComplexSampleSet) and outputs its complex conjugate.
The Congugate has no parameters to edit and therefore has no unit parameter window.


{% extends "includes/base.html" %} {% block page_title %}Logged Out!{% endblock page_title %} {% block content %}
Click here to login again.


Simple Agent
The SimpleAgent is a component that allows you to create characters that intelligently move along navigation meshes to their destinations.
To begin attach the SimpleAgent component to the game object.
| Inspector Property | Description |
|---|---|
| Layer | Defines which layer the agent belong to. |
| Area Mask | Specifies on which areas the agent can move. |
| Radius | Defines how close the agent center can get to edges of the navigation mesh. |
| Stopping Distance | The minimum distance to the target point to stop the movement. |
| Max Velocity | The maximum velocity magnitude. (How fast the agent can move.) |
| Max Acceleration | The maximum acceleration magnitude. (How fast the agent can gain speed.) |
| Rotation Speed | How fast the agent can rotate. |
| Draw Gizmos | If true , gizmos is drawn. |
Implementation example
As an example, consider a behavior where the agent is patrolling between two points. The code could look like this:
using AlchemyBow.Navigation.Simple;
using UnityEngine;
public class PatrolBehaviourExample : MonoBehaviour
{
[SerializeField]
private Vector3 checkpointA = Vector3.zero;
[SerializeField]
private Vector3 checkpointB = Vector3.zero;
[SerializeField]
private SimpleAgent agent = null;
private bool direction;
private void OnEnable()
{
agent.OnDestinationReached += OnCheckpoint;
OnCheckpoint();
}
private void OnDisable()
{
agent.OnDestinationReached -= OnCheckpoint;
agent.CancelAllRequests();
}
private void OnCheckpoint()
{
direction = !direction;
agent.SetDestination(direction ? checkpointA : checkpointB, false);
}
}
You should know
- The
SimpleAgent
does not provide avoidance behaviour it self. It is done with the help of movement modifiers. - You can create custom agents - see BasicAgent. However, in most cases the
SimpleAgent
is what you are looking for.


This class will involve a lot of coding, for which you will need some basic tools.
We will discuss these tools in much more detail in class, so don’t worry if this is all new and perhaps a bit frightening right now.
Python and Jupyter notebook
Python is a free programming language. We will use the distribution called Anaconda as it comes with the most essential for working with data, statistical computing and visualizations. We will use Anaconda for Python 3.7 throughout the course, so please make sure it is installed on your computer before first day of class. It works on all platforms.
Anaconda can be downloaded here, for Windows, Mac or Linux. If you want to watch a step-by-step tutorial on how to install Anaconda and Jupyter Notebook for you machine see the guides here:
- Install Anaconda for Windows by following these steps or watch this video
- Install Anaconda for Mac by following these steps or watch this video
Since the vast majority of our coding will be in the Python language, we will use an integrated development environment (IDE). IDEs integrate text editing, syntax highlighting, and version control, simplifying the coding process. These packages are automatically included in Anaconda Jupyter Notebook. It’s free and modern, and if you’re new to Python this will make it much easier to get started. All Python coding in this course will be done in Jupyter Notebook.
Verifying the installation
After installation of Python please to execute a number of commands in the shell. You need to first open your local shell, this is the Anaconda Prompt
on Windows or terminal
on Linux/Mac. See details here. Once the shell is open type python
- this will start Python. Once you have Python started please try the following two commands to verify that it’s working.
1+2
>>> 3
print('Welcome to Introduction to Social Data Science')
>>> Welcome to Introduction to Social Data Science
Welcome to open source
To know core Python is powerful in itself, but the great potentials lie in the huge community of developers and researchers contributing to a shared pool of software packages. A programming language is as powerful as the community that surrounds it. Especially in the field of machine learning, the Python community is leading the way, allowing you to share code with top researchers from the field and industry, among others Google’s top engineering teams. Tapping into these vast resources is made easy by the Conda distribution and the pip package manager. Just open your shell/command-line/terminal and type the following:
conda install [name of package]
or if conda does not support it directly use the more generic package manager:
pip install [name of package]
Using Jypyter notebook
The Jupyter Notebook App can be launched by clicking on the Jupyter Notebook icon installed by Anaconda in the start menu (only Windows) or by typing the following either in a terminal (on Mac/Linux) or cmd (on Windows).
jupyter notebook
This will launch a new browser window (or a new tab) showing the Notebook Dashboard, a sort of control panel that allows (among other things) to select which notebook to open.
Getting friendly with Jupyter
Try to spend a little time familiarizing yourself with the Jupyter framework. For instance, try learning a few of your editor’s keyboard shortcuts; see our post here. The point is to be as productive as possible when working with the computer. Karl Broman, a professor of biostatistics and medical informatics at the University of Wisconsin-Madison, gives some great advice for working with code:
The key thing I emphasize to students is they should be using the mouse as little as possible. Every time you move your hands away from the keys, you’re slowing yourself down.
A Git client
Git is a version control system that allows you to track modifications to files and code over time. It also facilitates collaborations so that multiple people can share and edit the same code base.
If you are on Windows you can install Github Desktop which provides both the command line tool for git and a graphical user interface. Alternatively, you can install git as an optional package under Cygwin. I recommend the Github application, as it will be easier to interface with Github using it. Likewise, modern versions of Mac OS X have a command line git client installed by default, but the Github Desktop tool is a recommended addition.
A Github account
Github is a platform that facilitates collaboration on projects that use git. You can use it to host projects, publish them to the web, and share them with other people. Create a free account if you don’t already have one.
Once you have an account, clone the course repository using your local git client. This is most easily done on the command line as follows:
# git clone https://github.com/abjer/isds2020
Cloning into 'isds2020'...
remote: Counting objects: 145, done.
remote: Compressing objects: 100% (98/98), done.
remote: Total 145 (delta 40), reused 137 (delta 37)
Receiving objects: 100% (145/145), 454.90 KiB | 594.00 KiB/s, done.
Resolving deltas: 100% (40/40), done.
Checking connectivity... done.
When this is complete, verify that you have a local directory called isds2021
containing a README.md
file.
Afterwards you can subscribe to updates, small and big, by using Watch
or Star
within the GitHub page.
A text editor (optional)
An important alternative to Jupyter is a decent text editor. A text editor is a program that lets you work with plain-text files. You should pick an editor capable of syntax highlighting, syntax checking (ensuring that brackets and parentheses are properly paired), and handling multiple files. We highly recommend:
Another good option is Sublime Text.
All three of these can be extended by installing “packages”. No matter your choice of editor it is a good idea to find and install extensions that are designed to help you with python programming.


Preprocessing - Determine the Current Density¶
The first thing which is required is to define the geometry of the cpw. In this code exapmle, we call the SetParams object, which reads a text file containing the relevant resonator parameters. We define a grid over the enntire resonator structure, and then calcualte analytically the current density and critical current for the cpw. These values are saved in a parameter listr which gets sent to COMSOL, and the datafiles are stored locally.
import csv
import os
import numpy as np
from qsd.electromagnetics import cpw
from qsd.data_processing import setparams
# Define geometry of the superconductor
setp = setparams.SetParams()
params = setp.set_params("cpw_parameters.txt")
w = params["w"]
t = params["t"]
l = params["l"]
pen = params["pen"]
omega = params["omega"]
Z = params["Z"]
# Define the 'mesh'
x = np.linspace(-w, w, int(1e04))
# Instantiate Special CPW object
cpw = cpw.CPW(x,l,w,t,pen,Z,omega)
Js = cpw.J() #s Current density - not normalised
Jnorm = cpw.normalize_J() # Normalise
I = cpw.current(norm='no') # Find the current
# Generate a parameter list for COMSOL modelling
paramlist = setp.param_list(x,I,Jnorm,'paramlist.txt') # Generate COMSOL parameter list
currentDensityFile = str(os.getcwd() + "/current_density.csv")
np.savetxt(currentDensityFile, np.column_stack((x,Jnorm)), delimiter=",")
currentFile = str(os.getcwd() + "/current.csv")
np.savetxt(currentFile, np.column_stack((x,I)), delimiter=",")