busybox - The Swiss Army Knife of Embedded Linux



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

will cause BusyBox to behave as ’ls’ (if the ’ls’ command has been compiled into BusyBox). Generally speaking, you should never need to make all these links yourself, as the BusyBox build system will do this for you when you run the ’make install’ command.

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.


Currently available applets include:

[, [[, acpid, add−shell, addgroup, adduser, adjtimex, arch, arp,
arping, ash, awk, base64, basename, bbconfig, bc, beep, blkdiscard,
blkid, blockdev, brctl, bunzip2, bzcat, bzip2, cal, cat, chattr,
chgrp, chmod, chown, chpasswd, chroot, chvt, cksum, clear, cmp,
comm, cp, cpio, crond, crontab, cryptpw, cut, date, dc, dd,
deallocvt, delgroup, deluser, depmod, df, diff, dirname, dmesg,
dnsdomainname, dos2unix, du, dumpkmap, echo, ed, egrep, eject, env,
ether−wake, expand, expr, factor, fallocate, false, fatattr, fbset,
fbsplash, fdflush, fdisk, fgrep, find, findfs, flock, fold, free,
fsck, fstrim, fsync, fuser, getopt, getty, grep, groups, gunzip,
gzip, halt, hd, head, hexdump, hostid, hostname, hwclock, id,
ifconfig, ifdown, ifenslave, ifup, init, inotifyd, insmod, install,
ionice, iostat, ip, ipaddr, ipcalc, ipcrm, ipcs, iplink, ipneigh,
iproute, iprule, iptunnel, kbd_mode, kill, killall, killall5, klogd,
last, less, link, linux32, linux64, ln, loadfont, loadkmap, logger,
login, logread, losetup, ls, lsattr, lsmod, lsof, lsusb, lzcat,
lzma, lzop, lzopcat, makemime, md5sum, mdev, mesg, microcom, mkdir,
mkdosfs, mkfifo, mkfs.vfat, mknod, mkpasswd, mkswap, mktemp,
modinfo, modprobe, more, mount, mountpoint, mpstat, mv, nameif,
nanddump, nandwrite, nbd−client, nc, netstat, nice, nl, nmeter,
nohup, nologin, nproc, nsenter, nslookup, ntpd, od, openvt,
partprobe, passwd, paste, pgrep, pidof, ping, ping6, pipe_progress,
pivot_root, pkill, pmap, poweroff, printenv, printf, ps, pscan,
pstree, pwd, pwdx, raidautorun, rdate, rdev, readahead, readlink,
realpath, reboot, reformime, remove−shell, renice, reset, resize,
rev, rfkill, rm, rmdir, rmmod, route, run−parts, sed, sendmail, seq,
setconsole, setfont, setkeycodes, setlogcons, setpriv, setserial,
setsid, sh, sha1sum, sha256sum, sha3sum, sha512sum, showkey, shred,
shuf, slattach, sleep, sort, split, stat, strings, stty, su, sum,
swapoff, swapon, switch_root, sync, sysctl, syslogd, tac, tail, tar,
tee, test, time, timeout, top, touch, tr, traceroute, traceroute6,
true, truncate, tty, ttysize, tunctl, udhcpc, udhcpc6, umount,
uname, unexpand, uniq, unix2dos, unlink, unlzma, unlzop, unshare,
unxz, unzip, uptime, usleep, uudecode, uuencode, vconfig, vi, vlock,
volname, watch, watchdog, wc, wget, which, who, whoami, whois,
xargs, xxd, xzcat, yes, zcat



acpid [−df] [−c CONFDIR ] [−l LOGFILE ] [−a ACTIONFILE ] [−M MAPFILE ] [−e PROC_EVENT_FILE ] [−p PIDFILE ]

Listen to ACPI events and spawn specific helpers on event arrival

−d Log to stderr, not log file (implies −f)
−f Run in foreground
−c DIR Config directory [/etc/acpi]
−e FILE /proc event file [/proc/acpi/event]
−l FILE Log file [/var/log/acpid.log]
−p FILE Pid file [/var/run/acpid.pid]
−a FILE Action file [/etc/acpid.conf]
−M FILE Map file [/etc/acpi.map]

Accept and ignore compatibility options −g −m −s −S −v


add-shell SHELL...

Add SHELLs to /etc/shells


addgroup [−g GID ] [−S] [ USER ] GROUP

Add a group or add a user to a group

−g GID Group id
−S Create a system group


adduser [ OPTIONS ] USER [ GROUP ]

Create new user, or add USER to GROUP

−h DIR Home directory
−g GECOS GECOS field
−s SHELL Login shell
−G GRP Group
−S Create a system user
−D Don't assign a password
−H Don't create home directory
−u UID User id
−k SKEL Skeleton directory (/etc/skel)


adjtimex [−q] [−o OFS ] [−f FREQ ] [−p TCONST ] [−t TICK ]

Read or set kernel time variables. See adjtimex(2)

−q Quiet
−o OFF Time offset, microseconds
−f FREQ Frequency adjust, integer kernel units (65536 is 1ppm)
−t TICK Microseconds per tick, usually 10000
(positive −t or −f values make clock run faster)



Print system architecture


arp [−vn] [−H HWTYPE ] [−i IF ] −a [ HOSTNAME ] [−v] [−i IF ] −d HOSTNAME [pub] [−v] [−H HWTYPE ] [−i IF ] −s HOSTNAME HWADDR [temp] [−v] [−H HWTYPE ] [−i IF ] −s HOSTNAME HWADDR [netmask MASK ] pub [−v] [−H HWTYPE ] [−i IF ] −Ds HOSTNAME IFACE [netmask MASK ] pub

Manipulate ARP cache

−a Display (all) hosts
−d Delete ARP entry
−s Set new entry
−v Verbose
−n Don't resolve names
−i IF Network interface
−A,−p AF Protocol family
−H HWTYPE Hardware address type


arping [−fqbDUA] [−c CNT ] [−w TIMEOUT ] [−I IFACE ] [−s SRC_IP ] DST_IP

Send ARP requests/replies

−f Quit on first ARP reply
−q Quiet
−b Keep broadcasting, don't go unicast
−D Exit with 1 if DST_IP replies
−U Unsolicited ARP mode, update your neighbors
−A ARP answer mode, update your neighbors
−c N Stop after sending N ARP requests
−w TIMEOUT Seconds to wait for ARP reply
−I IFACE Interface to use (default eth0)
−s SRC_IP Sender IP address
DST_IP Target IP address


ash [−il] [−|+Cabefmnuvx] [−|+o OPT ]... [−c ’ SCRIPT ’ [ ARG0 ARGS ] | FILE ARGS | −s ARGS ]

Unix shell interpreter


awk [ OPTIONS ] [ AWK_PROGRAM ] [ FILE ]...

−v VAR=VAL Set variable
−F SEP Use SEP as field separator
−f FILE Read program from FILE


base64 [−d] [−w COL ] [ FILE ]

Base64 encode or decode FILE to standard output

−d Decode data
−w COL Wrap lines at COL (default 76, 0 disables)


basename FILE [ SUFFIX ] | −a FILE... | −s SUFFIX FILE...

Strip directory path and SUFFIX from FILE

−a All arguments are FILEs
−s SUFFIX Remove SUFFIX (implies −a)



Print the config file used by busybox build


bc [−sqlw] [ FILE ]...

Arbitrary precision calculator

−q Quiet
−l Load standard library
−s Be POSIX compatible
−w Warn if extensions are used

$BC_LINE_LENGTH changes output width


beep −f FREQ −l LEN −d DELAY −r COUNT −n

−f Frequency in Hz
−l Length in ms
−d Delay in ms
−r Repetitions
−n Start new tone


blkdiscard [−o OFS ] [−l LEN ] [−s] DEVICE

Discard sectors on DEVICE

−o OFS Byte offset into device
−l LEN Number of bytes to discard
−s Perform a secure discard


blkid [ BLOCKDEV ]...

Print UUIDs of all filesystems



−−setro Set ro
−−setrw Set rw
−−getro Get ro
−−getss Get sector size
−−getbsz Get block size
−−setbsz BYTES Set block size
−−getsz Get device size in 512−byte sectors
−−getsize64 Get device size in bytes
−−getra Get readahead in 512−byte sectors
−−setra SECTORS Set readahead
−−flushbufs Flush buffers
−−rereadpt Reread partition table



Manage ethernet bridges Commands:

show [BRIDGE]... Show bridges
addbr BRIDGE Create BRIDGE
delbr BRIDGE Delete BRIDGE
showmacs BRIDGE List MAC addresses
showstp BRIDGE Show STP info
stp BRIDGE 1/yes/on|0/no/off Set STP on/off
setageing BRIDGE SECONDS Set ageing time
setfd BRIDGE SECONDS Set bridge forward delay
sethello BRIDGE SECONDS Set hello time
setmaxage BRIDGE SECONDS Set max message age
setbridgeprio BRIDGE PRIO Set bridge priority
setportprio BRIDGE IFACE PRIO Set port priority
setpathcost BRIDGE IFACE COST Set path cost


bunzip2 [−cfk] [ FILE ]...

Decompress FILEs (or stdin)

−c Write to stdout
−f Force
−k Keep input files
−t Test integrity


bzcat [ FILE ]...

Decompress to stdout


bzip2 [−cfkdt123456789] [ FILE ]...

Compress FILEs (or stdin) with bzip2 algorithm

−1..9 Compression level
−d Decompress
−c Write to stdout
−f Force
−k Keep input files
−t Test integrity


cal [−jmy] [[ MONTH ] YEAR ]

Display a calendar

−j Use julian dates
−m Week starts on Monday
−y Display the entire year


cat [−nbvteA] [ FILE ]...

Print FILEs to stdout

−n Number output lines
−b Number nonempty lines
−v Show nonprinting characters as ^x or M−x
−t ...and tabs as ^I
−e ...and end lines with $
−A Same as −vte


chattr [−R] [−v VERSION ] [−p PROJID ] [−+=AacDdijsStTu] FILE...

Change ext2 file attributes

−R Recurse
−v NUM Set version/generation number
−p NUM Set project number
−,+,= Remove/add/set attributes
A No atime
a Append only
C No copy−on−write
c Compressed
D Synchronous dir updates
d Don't backup with dump
E Encrypted
e File uses extents
F Case−insensitive dir
I Indexed dir
i Immutable
j Write data to journal first
N File is stored in inode
P Hierarchical project ID dir
S Synchronous file updates
s Zero storage when deleted
T Top of dir hierarchy
t Don't tail−merge with other files
u Allow undelete
V Verity


chgrp [−RhLHPcvf]... GROUP FILE...

Change the group membership of FILEs to GROUP

−h Affect symlinks instead of symlink targets
−L Traverse all symlinks to directories
−H Traverse symlinks on command line only
−P Don't traverse symlinks (default)
−R Recurse
−c List changed files
−v Verbose
−f Hide errors


chmod [−Rcvf] MODE[,MODE]... FILE...

MODE is octal number (bit pattern sstrwxrwxrwx) or [ugoa]{+|−|=}[rwxXst]

−R Recurse
−c List changed files
−v Verbose
−f Hide errors


chown [−RhLHPcvf]... USER[:[ GRP ]] FILE...

Change the owner and/or group of FILEs to USER and/or GRP

−h Affect symlinks instead of symlink targets
−L Traverse all symlinks to directories
−H Traverse symlinks on command line only
−P Don't traverse symlinks (default)
−R Recurse
−c List changed files
−v Verbose
−f Hide errors


chpasswd [−me] [−c ALG ] [−R DIR ]

Read user:password from stdin and update /etc/passwd

−e Supplied passwords are in encrypted form
−m Encrypt using md5, not des
−c ALG des,md5,sha256/512 (default sha512)
−R DIR Directory to chroot into



Run PROG with root directory set to NEWROOT


chvt N

Change the foreground virtual terminal to /dev/ttyN


cksum FILE...

Calculate CRC32 checksum of FILEs



Clear screen


cmp [−ls] [−n NUM ] FILE1 [ FILE2 [ SKIP1 [ SKIP2 ]]]

Compare FILE1 with FILE2 (or stdin)

−l Write the byte numbers (decimal) and values (octal)
for all differing bytes
−s Quiet
−n NUM Compare at most NUM bytes


comm [−123] FILE1 FILE2

Compare FILE1 with FILE2

−1 Suppress lines unique to FILE1
−2 Suppress lines unique to FILE2
−3 Suppress lines common to both files


cp [−arPLHpfinlsTu] SOURCE DEST or: cp [−arPLHpfinlsu] SOURCE... { −t DIRECTORY | DIRECTORY }


−a Same as −dpR
−R,−r Recurse
−d,−P Preserve symlinks (default if −R)
−L Follow all symlinks
−H Follow symlinks on command line
−p Preserve file attributes if possible
−f Overwrite
−i Prompt before overwrite
−n Don't overwrite
−l,−s Create (sym)links
−T Refuse to copy if DEST is a directory
−t DIR Copy all SOURCEs into DIR
−u Copy only newer files


cpio [−dmvu] [−F FILE ] [−R USER[:GRP]] [−H newc] [−tio] [−p DIR ] [ EXTR_FILE ]...

Extract (−i) or list (−t) files from a cpio archive, or take file list from stdin and create an archive (−o) or copy files (−p)

Main operation mode:

−t List
−i Extract EXTR_FILEs (or all)
−o Create (requires −H newc)
−p DIR Copy files to DIR
−H newc Archive format
−d Make leading directories
−m Restore mtime
−v Verbose
−u Overwrite
−F FILE Input (−t,−i,−p) or output (−o) file
−R USER[:GRP] Set owner of created files
−L Dereference symlinks
−0 NUL terminated input


crond [−fbS] [−l N] [−d N] [−L LOGFILE ] [−c DIR ]

−f Foreground
−b Background (default)
−S Log to syslog (default)
−l N Set log level. Most verbose 0, default 8
−d N Set log level, log to stderr
−c DIR Cron dir. Default:/var/spool/cron/crontabs


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 [−P FD ] [−m TYPE ] [−S SALT ] [ PASSWORD ] [ SALT ]

Print crypt(3) hashed PASSWORD

−P N Read password from fd N
−m TYPE des,md5,sha256/512 (default sha512)


cut [ OPTIONS ] [ FILE ]...

Print selected fields from FILEs to stdout

−b LIST Output only bytes from LIST
−c LIST Output only characters from LIST
−d SEP Field delimiter for input (default −f TAB, −F run of whitespace)
−O SEP Field delimeter for output (default = −d for −f, one space for −F)
−D Don't sort/collate sections or match −fF lines without delimeter
−f LIST Print only these fields (−d is single char)
−s Output only lines containing delimiter
−n Ignored


date [ OPTIONS ] [+FMT] [[−s] TIME ]

Display time (using +FMT), or set time

−u Work in UTC (don't convert to local time)
[−s] TIME Set time to TIME
−d TIME Display TIME, not 'now'
−D FMT FMT (strptime format) for −s/−d TIME conversion
−r FILE Display last modification time of FILE
−R Output RFC−2822 date
−I[SPEC] Output ISO−8601 date
SPEC=date (default), hours, minutes, seconds or ns

Recognized TIME formats:

YYYY−MM−DD hh:mm[:ss]
'date TIME' form accepts MMDDhhmm[[YY]YY][.ss] instead


dc [−x] [−eSCRIPT]... [−fFILE]... [ FILE ]...

Tiny RPN calculator. Operations: Arithmetic: + − * / % ^ ~ − divide with remainder | − modular exponentiation v − square root p − print top of the stack without popping f − print entire stack k − pop the value and set precision i − pop the value and set input radix o − pop the value and set output radix Examples: dc −e’2 2 + p’ −> 4, dc −e’8 8 * 2 2 + / p’ −> 16


dd [if=FILE] [of=FILE] [ibs=N obs=N/bs=N] [count=N] [skip=N] [seek=N] [conv=notrunc|noerror|sync|fsync] [iflag=skip_bytes|count_bytes|fullblock|direct] [oflag=seek_bytes|append|direct]

Copy a file with converting and formatting

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
conv=swab Swap every pair of bytes
iflag=skip_bytes skip=N is in bytes
iflag=count_bytes count=N is in bytes
oflag=seek_bytes seek=N is in bytes
iflag=direct O_DIRECT input
oflag=direct O_DIRECT output
iflag=fullblock Read full blocks
oflag=append Open output in append mode
status=noxfer Suppress rate output
status=none Suppress all output

N may be suffixed by c (1), w (2), b (512), kB (1000), k (1024), MB, M, GB, G


deallocvt [N]

Deallocate unused virtual terminal /dev/ttyN


delgroup [ USER ] GROUP

Delete group GROUP from the system or user USER from group GROUP


deluser [−−remove−home] USER

Delete USER from the system


depmod [−n] [−b BASE ] [ VERSION ] [ MODFILES ]...

Generate modules.dep, alias, and symbols files

−b BASE Use BASE/lib/modules/VERSION
−n Dry run: print files to stdout


df [−PkmhTai] [−B SIZE ] [−t TYPE ] [ FILESYSTEM ]...

Print filesystem usage statistics

−P POSIX output format
−k 1024−byte blocks (default)
−m 1M−byte blocks
−h Human readable (e.g. 1K 243M 2G)
−T Print filesystem type
−t TYPE Print only mounts of this type
−a Show all filesystems
−i Inodes
−B SIZE Blocksize


diff [−abBdiNqrTstw] [−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.

−a Treat all files as text
−b Ignore changes in the amount of whitespace
−B Ignore changes whose lines are all blank
−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 Recurse
−−no−dereference Don't follow symlinks
−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 [−cr] [−n LEVEL ] [−s SIZE ]

Print or control the kernel ring buffer

−c Clear ring buffer after printing
−n LEVEL Set console logging level
−s SIZE Buffer size
−r Print raw message buffer


dos2unix [−ud] [ FILE ]

Convert FILE in-place from DOS to Unix format. When no file is given, use stdin/stdout.

−u dos2unix
−d unix2dos


du [−aHLdclsxhmk] [ FILE ]...

Summarize disk space used for FILEs (or directories)

−a Show file sizes too
−b Apparent size (including holes)
−L Follow all symlinks
−H Follow symlinks on command line
−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 stdout


echo [−neE] [ ARG ]...

Print ARGs to stdout

−n No trailing newline
−e Interpret backslash escapes (\t=tab etc)
−E Don't interpret backslash escapes (default)


ed [−p PROMPT ] [ FILE ]


eject [−t] [−T] [ DEVICE ]

Eject DEVICE or default /dev/cdrom

−s SCSI device
−t Close tray
−T Open/close tray (toggle)


env [−i0] [−u NAME ]... [−] [NAME=VALUE]... [ PROG ARGS ]

Print current environment or run PROG after setting up environment

−, −i Start with empty environment
−0 NUL terminated output
−u NAME Remove variable from environment


ether-wake [−b] [−i IFACE ] [−p aa:bb:cc:dd[:ee:ff]/a.b.c.d] MAC

Send a magic packet to wake up sleeping machines. MAC must be a station address (00:11:22:33:44:55) or a hostname with a known ’ethers’ entry.

−b Broadcast the packet
−i IFACE Interface to use (default eth0)
−p PASSWORD Append four or six byte PASSWORD to the packet


expand [−i] [−t N] [ FILE ]...

Convert tabs to spaces, writing to stdout

−i Don't convert tabs after non blanks
−t Tabstops every N chars



Print the value of EXPRESSION


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 Sum of ARG1 and ARG2. Similarly:
STRING : REGEXP Anchored pattern match of REGEXP in STRING
substr STRING POS LEN Substring of STRING, POS counts 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 '/'

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.


factor [ NUMBER ]...

Print prime factors


fallocate [−o OFS ] −l LEN FILE

Preallocate space for FILE

−o OFS Offset of range
−l LEN Length of range


fatattr [−+rhsvda] FILE...

Change file attributes on FAT filesystem

− Clear attributes
+ Set attributes
r Read only
h Hidden
s System
v Volume label
d Directory
a Archive


fbset [ OPTIONS ] [ MODE ]

Show and modify frame buffer settings


fbsplash −s IMGFILE [−c] [−d DEV ] [−i INIFILE ] [−f CMD ] [−T tty]

−s Image
−c Hide cursor
−d Framebuffer device (default /dev/fb0)
−i Config file (var=value):
−f Control pipe (else exit after drawing image)
commands: 'NN' (% for progress bar) or 'exit'
−T Switch to TTY to hide all console messages


fdflush DEVICE

Force floppy disk drive to detect disk change


fdisk [−ul] [−C CYLINDERS ] [−H HEADS ] [−S SECTORS ] [−b SSZ ] DISK

Change partition table

−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 Typically 255
−S SECTORS Typically 63


find [−HL] [ PATH ]... [ OPTIONS ] [ ACTIONS ]

Search for files and perform actions on them. First failed action stops processing of current file. Defaults: PATH is current directory, action is ’−print’

−L,−follow Follow symlinks
−H ...on command line only
−xdev Don't descend directories on other filesystems
−maxdepth N Descend at most N levels. −maxdepth 0 applies
actions to command line arguments only
−mindepth N Don't act on first N levels
−depth Act on directory *after* traversing it


( ACTIONS ) Group actions for −o / −a
! ACT Invert ACT's success/failure
ACT1 [−a] ACT2 If ACT1 fails, stop, else do ACT2
ACT1 −o ACT2 If ACT1 succeeds, stop, else do ACT2
Note: −a has higher priority than −o
−name PATTERN Match file name (w/o directory name) to PATTERN
−iname PATTERN Case insensitive −name
−path PATTERN Match path to PATTERN
−ipath PATTERN Case insensitive −path
−regex PATTERN Match path to regex PATTERN
−type X File type is X (one of: f,d,l,b,c,s,p)
−executable File is executable
−perm MASK At least one mask bit (+MASK), all bits (−MASK),
or exactly MASK bits are set in file's mode
−mtime DAYS mtime is greater than (+N), less than (−N),
or exactly N days in the past
−atime DAYS atime +N/−N/N days in the past
−ctime DAYS ctime +N/−N/N days in the past
−mmin MINS mtime is greater than (+N), less than (−N),
or exactly N minutes in the past
−newer FILE mtime is more recent than FILE's
−inum N File has inode number N
−user NAME/ID File is owned by given user
−group NAME/ID File is owned by given group
−size N[bck] File size is N (c:bytes,k:kbytes,b:512 bytes(def.))
+/−N: file size is bigger/smaller than N
−links N Number of links is greater than (+N), less than (−N),
or exactly N
−empty Match empty file/directory
−prune If current file is directory, don't descend into it
If none of the following actions is specified, −print is assumed
−print Print file name
−print0 Print file name, NUL terminated
−exec CMD ARG ; Run CMD with all instances of {} replaced by
file name. Fails if CMD exits with nonzero
−exec CMD ARG + Run CMD with {} replaced by list of file names
−delete Delete current file/directory. Turns on −depth option
−quit Exit


findfs LABEL=label or UUID=uuid

Find a filesystem device based on a label or UUID


flock [−sxun] FD | { FILE [−c] PROG ARGS }

[Un]lock file descriptor, or lock FILE, run PROG

−s Shared lock
−x Exclusive lock (default)
−u Unlock FD
−n Fail rather than wait


fold [−bs] [−w WIDTH ] [ FILE ]...

Wrap input lines in FILEs (or stdin), writing to stdout

−b Count bytes rather than columns
−s Break at spaces
−w Use WIDTH columns instead of 80


free [−bkmgh]

Display free and used memory


fsck [−ANPRTV] [−t FSTYPE ] [ FS_OPTS ] [ BLOCKDEV ]...

Check and repair filesystems

−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
−t TYPE List of filesystem types to check



−o OFFSET Offset in bytes to discard from
−l LEN Bytes to discard
−m MIN Minimum extent length
−v Print number of discarded bytes


fsync [−d] FILE...

Write all buffered blocks in FILEs to disk

−d Avoid syncing metadata


fuser [−msk46] [−SIGNAL] FILE or PORT/PROTO

Find processes which use FILEs or PORTs

−m Find processes which use same fs as FILEs
−4,−6 Search only IPv4/IPv6 space
−s Don't display PIDs
−k Kill found processes
−SIGNAL Signal to send (default: KILL)



−a Allow long options starting with single −
−l LOPT[,...] Long options to recognize
−n PROGNAME The name under which errors are reported
−o OPTSTRING Short options to recognize
−q No error messages on unrecognized options
−Q No normal output
−s SHELL Set shell quoting conventions
−T Version test (exits with 4)
−u Don't quote output


O=‘getopt −l bb: -- ab:c:: "$@"‘ || exit 1 eval set -- "$O" while true; do

case "$1" in


echo A; shift;;

−b|−−bb) echo "B:’$2’"; shift 2;;


case "$2" in


echo C; shift 2;;


echo "C:’$2’"; shift 2;;



shift; break;;


echo Error; exit 1;;

esac done



Open TTY, prompt for login name, then invoke /bin/login

−h Enable hardware RTS/CTS flow control
−L Set CLOCAL (ignore Carrier Detect state)
−m Get baud rate from modem's CONNECT status message
−n Don't prompt for login name
−w Wait for CR or LF before sending /etc/issue
−i Don't display /etc/issue
−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 login name is read
−I INITSTR Send INITSTR before anything else
−H HOST Log HOST into the utmp file as the hostname

BAUD_RATE of 0 leaves it unchanged


grep [−HhnlLoqvsrRiwFE] [−m N] [−A|B|C N] { PATTERN | −e PATTERN... | −f FILE... } [ FILE ]...

Search for PATTERN in FILEs (or stdin)

−H Add 'filename:' prefix
−h Do not add 'filename:' prefix
−n Add 'line_no:' prefix
−l Show only names of files that match
−L Show only names of files that don't match
−c Show only count of matching lines
−o Show only the matching part of line
−q Quiet. Return 0 if PATTERN is found, 1 otherwise
−v Select non−matching lines
−s Suppress open and read errors
−r Recurse
−R Recurse and dereference symlinks
−i Ignore case
−w Match whole words only
−x Match whole lines only
−F PATTERN is a literal (not regexp)
−E PATTERN is an extended regexp
−m N Match up to N times per file
−A N Print N lines of trailing context
−B N Print N lines of leading context
−C N Same as '−A N −B N'
−e PTRN Pattern to match
−f FILE Read pattern from file


groups [ USER ]

Print the groups USER is in


gunzip [−cfkt] [ FILE ]...

Decompress FILEs (or stdin)

−c Write to stdout
−f Force
−k Keep input files
−t Test integrity


gzip [−cfkdt123456789] [ FILE ]...

Compress FILEs (or stdin)

−1..9 Compression level
−d Decompress
−c Write to stdout
−f Force
−k Keep input files
−t Test integrity


halt [−d DELAY ] [−nfw]

Halt the system

−d SEC Delay interval
−n Do not sync
−f Force (don't go through init)
−w Only write a wtmp record


hd FILE...

hd is an alias for hexdump −C


head [ OPTIONS ] [ FILE ]...

Print first 10 lines of FILEs (or stdin). With more than one FILE, precede each with a filename header.

−n N[bkm] Print first N lines
−n −N[bkm] Print all except N last lines
−c [−]N[bkm] Print first N bytes
(b:*512 k:*1024 m:*1024^2)
−q Never print headers
−v Always print headers


hexdump [−bcdoxCv] [−e FMT ] [−f FMT_FILE ] [−n LEN ] [−s OFS ] [ FILE ]...

Display FILEs (or stdin) in a user specified format

−b 1−byte octal display
−c 1−byte character display
−d 2−byte decimal display
−o 2−byte octal display
−x 2−byte hex display
−C hex+ASCII 16 bytes per line
−v Show all (no dup folding)
−e FORMAT_STR Example: '16/1 "%02x|""\n"'
−n LENGTH Show only first LENGTH bytes
−s OFFSET Skip OFFSET bytes



Print out a unique 32−bit identifier for the machine


hostname [−sidf] [ HOSTNAME | −F FILE ]

Show or set hostname or DNS domain name

−s Short
−i Addresses for the hostname
−d DNS domain name
−f Fully qualified domain name
−F FILE Use FILE's content as hostname


hwclock [−swul] [−−systz] [−f DEV ]

Show or set hardware clock ( RTC )

−s Set system time from RTC
−w Set RTC from system time
−−systz Set in−kernel timezone, correct system time
if RTC is kept in local time
−f DEV Use specified device (e.g. /dev/rtc2)
−u Assume RTC is kept in UTC
−l Assume RTC is kept in local time
(if neither is given, read from /var/lib/hwclock/adjtime)


id [−ugGnr] [ USER ]

Print information about USER or the current user

−u User ID
−g Group ID
−G Supplementary group IDs
−n Print names instead of numbers
−r Print real ID instead of effective ID


ifconfig [−a] [ IFACE ] [ ADDRESS ]

Configure a network interface

[[−]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 [−nvf] [−i FILE ] −a | IFACE...

−a Deconfigure all interfaces
−i FILE Use FILE instead of /etc/network/interfaces
−n Dry run
−v Print out what would happen before doing it
−f Force


ifenslave [−cdf] MASTER_IFACE SLAVE_IFACE...

Configure network interfaces for parallel routing

−c Change active slave
−d Remove slave interface from bonding device
−f Force, even if interface is not Ethernet


ifup [−nvf] [−i FILE ] −a | IFACE...

−a Configure all interfaces
−i FILE Use FILE instead of /etc/network/interfaces
−n Dry run
−v Print out what would happen before doing it
−f Force



Init is the first process started during boot. It never exits. It (re)spawns children according to /etc/inittab. Signals:

HUP: reload /etc/inittab TSTP: stop respawning until CONT QUIT: re-exec another init USR1/TERM/USR2/INT: run halt/reboot/poweroff/Ctrl−Alt−Del script


inotifyd PROG FILE1[:MASK]...

Run PROG on filesystem changes. When a filesystem event matching MASK occurs on FILEn, PROG ACTUAL_EVENTS FILEn [ SUBFILE ] is run. If PROG is −, events are sent to stdout. 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:
y Subfile is moved into dir
m 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.



Load kernel module


install [−cdDsp] [−o USER ] [−g GRP ] [−m MODE ] [−t DIR ] [ SOURCE ]... DEST

Copy files and set attributes

−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
−t DIR Install to DIR


ionice [−c 1−3] [−n 0−7] [−t] { −p PID | PROG ARGS }

Change I/O priority and class

−c N Class. 1:realtime 2:best−effort 3:idle
−n N Priority
−t Ignore errors


iostat [−c] [−d] [−t] [−z] [−k|−m] [ALL|BLOCKDEV...] [ INTERVAL [ COUNT ]]

Report CPU and I/O statistics

−c Show CPU utilization
−d Show device utilization
−t Print current time
−z Omit devices with no activity
−k Use kb/s
−m Use Mb/s


ip [ OPTIONS ] address|route|link|tunnel|neigh|rule [ ARGS ]

OPTIONS := −f[amily] inet|inet6|link | −o[neline]

ip addr add|del IFADDR dev IFACE | show|flush [dev IFACE ] [to PREFIX ] ip route list|flush|add|del|change|append|replace|test ROUTE ip link set IFACE [up|down] [arp on|off] [multicast on|off] [promisc on|off] [mtu NUM ] [name NAME ] [qlen NUM ] [address MAC ] [master IFACE | nomaster] [netns PID ] ip tunnel add|change|del|show [ NAME ] [mode ipip|gre|sit] [remote ADDR ] [local ADDR ] [ttl TTL ] ip neigh show|flush [to PREFIX ] [dev DEV ] [nud STATE ] ip rule [list] | add|del SELECTOR ACTION


ipaddr add|del IFADDR dev IFACE | show|flush [dev IFACE ] [to PREFIX ]

ipaddr add|change|replace|delete dev IFACE [ CONFFLAG−LIST ] IFADDR IFADDR := PREFIX | ADDR peer PREFIX [broadcast ADDR|+|−] [anycast ADDR ] [label STRING ] [scope SCOPE ] PREFIX := ADDR[/MASK] SCOPE := [host|link|global|NUMBER] CONFFLAG-LIST := [ CONFFLAG−LIST ] CONFFLAG CONFFLAG := [noprefixroute] ipaddr show|flush [dev IFACE ] [scope SCOPE ] [to PREFIX ] [label PATTERN ]


ipcalc [−bnmphs] ADDRESS[/PREFIX] [ NETMASK ]

Calculate and display network settings from IP address

−b Broadcast address
−n Network address
−m Default netmask for IP
−p Prefix for IP/NETMASK
−h Resolved host name
−s No 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.

−mM Remove memory segment after last detach
−qQ Remove message queue
−sS Remove semaphore


ipcs [[−smq] −i SHMID ] | [[−asmq] [−tcplu]]

−i ID 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 IFACE [up|down] [arp on|off] [multicast on|off]

[promisc on|off] [mtu NUM ] [name NAME ] [qlen NUM ] [address MAC ]

[master IFACE | nomaster] [netns PID ] iplink add [link IFACE ] IFACE [address MAC ] type TYPE [ ARGS ] iplink delete IFACE type TYPE [ ARGS ]

TYPE ARGS := vlan VLANARGS | vrf table NUM

VLANARGS := id VLANID [protocol 802.1q|802.1ad] [reorder_hdr on|off]

[gvrp on|off] [mvrp on|off] [loose_binding on|off] iplink show [ IFACE ]


ipneigh show|flush [to PREFIX ] [dev DEV ] [nud STATE ]


iproute list|flush|add|del|change|append|replace|test ROUTE

iproute list|flush SELECTOR

SELECTOR := [root PREFIX ] [match PREFIX ] [proto RTPROTO ]

PREFIX := default|ADDR[/MASK] iproute get ADDR [from ADDR iif IFACE ]

[oif IFACE ] [tos TOS ] iproute add|del|change|append|replace|test ROUTE


NODE_SPEC := PREFIX [table TABLE_ID ] [proto RTPROTO ] [scope SCOPE ] [metric METRIC ]


NH := [via [inet|inet6] ADDR ] [dev IFACE ] [src ADDR ] [onlink]

OPTIONS := [mtu [lock] NUM ] [advmss [lock] NUM ]


iprule [list] | add|del SELECTOR ACTION

SELECTOR := [from PREFIX] [to PREFIX] [tos TOS] [fwmark FWMARK[/MASK]]
[dev IFACE] [pref NUMBER]
ACTION := [table TABLE_ID] [nat ADDR]
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 VT console keyboard mode

−a Default (ASCII)
−k Medium−raw (keycode)
−s Raw (scancode)
−u Unicode (utf−8)
−C TTY Affect TTY


kill [−l] [−SIG] PID...

Send a signal (default: TERM ) to given PIDs

−l List all signal names and numbers


killall [−lq] [−SIG] PROCESS_NAME...

Send a signal (default: TERM ) to given processes

−l List all signal names and numbers
−q Don't complain if no processes were killed


killall5 [−l] [−SIG] [−o PID ]...

Send a signal (default: TERM ) to all processes outside current session

−l List all signal names and numbers
−o PID Don't signal this PID


klogd [−c N] [−n]

Log kernel messages to syslog

−c N Print to console messages more urgent than prio N (1−8)
−n Run in foreground



Show listing of the last users that logged into the system


less [−EFIMmNSRh~] [ FILE ]...

View FILE (or stdin) one screenful at a time

−E Quit once the end of a file is reached
−F Quit if entire file fits on first screen
−I Ignore case in all searches
−M,−m Display status line with line numbers
and percentage through the file
−N Prefix line number to each line
−S Truncate long lines
−R Remove color escape codes in input
−~ Suppress ~s displayed past EOF



Create hard LINK to FILE


ln [−sfnbtv] [−S SUF ] TARGET... LINK|DIR

Create a link LINK or DIR/TARGET to the specified TARGET (s)

−s Make symlinks instead of hardlinks
−f Remove existing destinations
−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
−T Treat LINK as a file, not DIR
−v Verbose


loadfont < font

Load a console font from stdin


loadkmap < keymap

Load a binary keyboard translation table from stdin


logger [−s] [−t TAG ] [−p PRIO ] [ MESSAGE ]

Write MESSAGE (or stdin) to syslog

−s Log to stderr as well as the system log
−t TAG Log using the specified tag (defaults to user name)
−p PRIO Priority (number or FACILITY.LEVEL pair)


login [−p] [−h HOST ] [[−f] USER ]

Begin a new session on the system

−f Don't authenticate (user already authenticated)
−h HOST Host user came from (for network logins)
−p Preserve environment


Seconds (default 60, 0 − disable) $LOGIN_PRE_SUID_SCRIPT

Execute before user ID change


logread [−fF]

Show messages in syslogd’s circular buffer

−f Output data as log grows
−F Same as −f, but dump buffer first


losetup [−rP] [−o OFS ] {−f|LOOPDEV} FILE: associate loop devices

losetup −c LOOPDEV: reread file size

losetup −d LOOPDEV: disassociate

losetup −a: show status

losetup −f: show next free loop device

−o OFS Start OFS bytes into FILE
−P Scan for partitions
−r Read−only
−f Show/use next free loop device


ls [−1AaCxdLHRFplinshrSXvctu] [−w WIDTH ] [ FILE ]...

List directory contents

−1 One column output
−a Include names starting with .
−A Like −a, but exclude . and ..
−x List by lines
−d List directory names, not contents
−L Follow symlinks
−H Follow symlinks on command line
−R Recurse
−p Append / to directory names
−F Append indicator (one of */=@|) to names
−l Long format
−i List inode numbers
−n List numeric UIDs and GIDs instead of names
−s List allocated blocks
−lc List ctime
−lu List atime
−−full−time List full date/time
−h Human readable sizes (1K 243M 2G)
−S Sort by size
−X Sort by extension
−v Sort by version
−t Sort by mtime
−tc Sort by ctime
−tu Sort by atime
−r Reverse sort order
−w N Format N columns wide


lsattr [−Radlpv] [ FILE ]...

List ext2 file attributes

−R Recurse
−a Include names starting with .
−d List directory names, not contents
−l List long flag names
−p List project ID
−v List version/generation number



List loaded kernel modules



Show all open files


lzcat [ FILE ]...

Decompress to stdout


lzma −d [−cfk] [ FILE ]...

Decompress FILEs (or stdin)

−d Decompress
−c Write to stdout
−f Force
−k Keep input files
−t Test integrity


lzop [−cfUvd123456789CF] [ FILE ]...

−1..9 Compression level
−d Decompress
−c Write to stdout
−f Force
−U Delete input files
−v Verbose
−F Don't store or verify checksum
−C Also write checksum of compressed block


lzopcat [−vF] [ FILE ]...

−v Verbose
−F Don't verify checksum


makemime [ OPTIONS ] [ FILE ]...

Create multipart MIME-encoded message from FILEs

−o FILE Output. Default: stdout
−a HDR Add header(s). Examples:
"From: [email protected]", "Date: `date −R`"
−c CT Content type. Default: application/octet−stream
−C CS Charset. Default: us−ascii

Other options are silently ignored


md5sum [−c[sw]] [ FILE ]...

Print or check MD5 checksums

−c Check sums against list in FILEs
−s Don't output anything, status code shows success
−w Warn about improperly formatted checksum lines


mdev [−vS] { [−s] | [−df] }

−v Verbose
−S Log to syslog too
−s Scan /sys and populate /dev
−d Daemon, listen on netlink
−f Run in foreground

Bare mdev is a kernel hotplug helper. To activate it:

echo /sbin/mdev >/proc/sys/kernel/hotplug

It uses /etc/mdev.conf with lines

[−][ENV=regex;]...DEVNAME UID:GID PERM [>|=PATH]|[!] [@|$|*PROG] where DEVNAME is device name regex, @major,minor[−minor2], or environment variable regex. A common use of the latter is to load modules for hotplugged devices:

$MODALIAS=.* 0:0 660 @modprobe "$MODALIAS"

If /dev/mdev.seq file exists, mdev will wait for its value to match $SEQNUM variable. This prevents plug/unplug races. To activate this feature, create empty /dev/mdev.seq at boot.

If /dev/mdev.log file exists, debug log will be appended to it.


mesg [y|n]

Control write access to your terminal


Allow write access to your terminal


Disallow write access to your terminal


microcom [−d DELAY_MS ] [−t TIMEOUT_MS ] [−s SPEED ] [−X] TTY

Copy bytes from stdin to TTY and from TTY to stdout

−d DELAY Wait up to DELAY ms for TTY output before sending
every next byte to it
−t TIMEOUT Exit if both stdin and TTY are silent for TIMEOUT ms
−s SPEED Set serial line to SPEED
−X Disable special meaning of NUL and Ctrl−X from stdin


mkdir [−m MODE ] [−p] DIRECTORY...


−m MODE Mode
−p No error if exists; make parent directories as needed


mkdosfs [−v] [−n LABEL ] BLOCKDEV [ KBYTES ]

Make a FAT32 filesystem

−v Verbose
−n LBL Volume label


mkfifo [−m MODE ] NAME

Create named pipe

−m MODE Mode (default a=rw)


mkfs.vfat [−v] [−n LABEL ] BLOCKDEV [ KBYTES ]

Make a FAT32 filesystem

−v Verbose
−n LBL Volume label



Create a special file (block, character, or pipe)

−m MODE Creation mode (default a=rw)
b Block device
c or u Character device
p Named pipe (MAJOR MINOR must be omitted)


mkpasswd [−P FD ] [−m TYPE ] [−S SALT ] [ PASSWORD ] [ SALT ]

Print crypt(3) hashed PASSWORD

−P N Read password from fd N
−m TYPE des,md5,sha256/512 (default sha512)


mkswap [−L LBL ] BLOCKDEV [ KBYTES ]

Prepare BLOCKDEV to be used as swap partition

−L LBL Label


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). Without TEMPLATE, −t tmp.XXXXXX is assumed.

−d Make directory, not file
−q Fail silently on errors
−t Prepend base directory name to TEMPLATE
−p DIR Use DIR as a base directory (implies −t)
−u Do not create anything; print a name

Base directory is: −p DIR, else $TMPDIR, else /tmp


modinfo [−adlpn0] [−F keyword] [−k kernel] MODULE

−a Shortcut for '−F author'
−d Shortcut for '−F description'
−l Shortcut for '−F license'
−p Shortcut for '−F parm'
−F keyword Keyword to look for
−k kernel kernel version
−0 NUL terminated output


modprobe [−alrqvsDb] MODULE [SYMBOL=VALUE]...

−a Load multiple MODULEs
−l List (MODULE is a pattern)
−r Remove MODULE (stacks) or do autoclean
−q Quiet
−v Verbose
−s Log to syslog
−D Show dependencies
−b Apply blacklist to module names too


more [ FILE ]...

View FILE (or stdin) one screenful at a time



Mount a filesystem. Filesystem autodetection requires /proc.

−a Mount all filesystems in fstab
−f Dry run
−i Don't run mount helper
−v Verbose
−r Read−only mount
−t FSTYPE[,...] Filesystem type(s)
−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
[r]bind Bind a file or directory [recursively] to another location
move Relocate an existing mount point
remount Remount a mounted filesystem, changing flags
ro Same as −r

There are filesystem-specific −o flags.


mountpoint [−q] { [−dn] DIR | −x DEVICE }

Check if DIR is a mountpoint

−q Quiet
−d Print major:minor of the filesystem
−n Print device name of the filesystem
−x Print major:minor of DEVICE


mpstat [−A] [−I SUM|CPU|ALL|SCPU] [−u] [−P num|ALL] [ INTERVAL [ COUNT ]]

Per-processor statistics

−A Same as −I ALL −u −P ALL
−I SUM|CPU|ALL|SCPU Report interrupt statistics
−P num|ALL Processor to monitor
−u Report CPU utilization


mv [−finT] SOURCE DEST or: mv [−fin] SOURCE... { −t DIRECTORY | DIRECTORY }


−f Don't prompt before overwriting
−i Interactive, prompt before overwrite
−n Don't overwrite an existing file
−T Refuse to move if DEST is a directory
−t DIR Move all SOURCEs into DIR


nameif [−s] [−c FILE ] [ IFNAME SELECTOR ]...

Rename network interface while it in the down state. The device matched by SELECTOR is renamed to IFNAME. SELECTOR can be a combination of:

−c FILE Configuration file (default: /etc/mactab)
−s Log to syslog


nanddump [−no] [−−bb padbad|skipbad] [−s ADDR ] [−l LEN ] [−f FILE ] MTD_DEVICE


−n Read without ecc
−o Dump oob data
−s ADDR Start address
−l LEN Length
−f FILE Dump to file ('−' for stdout)
skipbad: skip bad blocks
padbad: substitute bad blocks by 0xff (default)


nandwrite [−np] [−s ADDR ] MTD_DEVICE [ FILE ]


−n Write without ecc
−p Pad to page size
−s ADDR Start address


nbd-client { [−b BLKSIZE ] [−N NAME ] [−t SEC ] [−p] HOST [ PORT ] | −d } BLOCKDEV

Connect to HOST and provide network block device on BLOCKDEV


nc [ OPTIONS ] HOST PORT − connect nc [ OPTIONS ] −l −p PORT [ HOST ] [ PORT ] − listen

−e PROG Run PROG after connect (must be last)
−l Listen mode, for inbound connects
−lk With −e, provides persistent server
−p PORT Local port
−s ADDR Local address
−w SEC Timeout for connects and final net reads
−i SEC Delay interval for lines sent
−n Don't do DNS resolution
−u UDP mode
−b Allow broadcasts
−v Verbose
−o FILE Hex dump traffic
−z Zero−I/O mode (scanning)


netstat [−ral] [−tuwx] [−enWp]

Display networking information

−r Routing table
−a All sockets
−l Listening sockets
Else: connected sockets
−t TCP sockets
−u UDP sockets
−w Raw sockets
−x Unix sockets
Else: all socket types
−e Other/more information
−n Don't resolve names
−W Wide display
−p Show PID/program name for sockets


nice [−n ADJUST ] [ PROG ARGS ]

Change scheduling priority, run PROG

−n ADJUST Adjust priority by ADJUST


nl [ OPTIONS ] [ FILE ]...

Write FILEs to standard output with line numbers added

−b STYLE Which lines to number − a: all, t: nonempty, n: none
−i N Line number increment
−s STRING Use STRING as line number separator
−v N Start from N
−w N Width of line numbers



Monitor system in real time

−d MSEC Milliseconds between updates, default:1000, none:−1

Format specifiers:

%Nc or %[cN] CPU. N − bar size (default 10)
(displays: S:system U:user N:niced D:iowait I:irq i:softirq)
%m Allocated memory
%[mf] Free memory
%[mt] Total memory
%s Allocated swap
%f Number of used file descriptors
%Ni Total/specific IRQ rate
%x Context switch rate
%p Forks
%[pn] # of processes
%b Block io
%Nt Time (with N decimal points)
%NT Zero−based timestamp (with N decimal points)
%r Print <cr> instead of <lf> at EOL



Run PROG immune to hangups, with output to a non-tty



Politely refuse a login


nproc [−−all] [−−ignore=N]

Print number of available CPUs

−−all Number of installed CPUs
−−ignore=N Exclude N CPUs


nsenter [ OPTIONS ] [ PROG ARGS ]

−t PID Target process to get namespaces from
−m[FILE] Enter mount namespace
−u[FILE] Enter UTS namespace (hostname etc)
−i[FILE] Enter System V IPC namespace
−n[FILE] Enter network namespace
−p[FILE] Enter pid namespace
−U[FILE] Enter user namespace
−S UID Set uid in entered namespace
−G GID Set gid in entered namespace
−−preserve−credentials Don't touch uids or gids
−r[DIR] Set root directory
−w[DIR] Set working directory
−F Don't fork before exec'ing PROG


nslookup [−type=QUERY_TYPE] [−debug] HOST [ DNS_SERVER ]

Query DNS about HOST

QUERY_TYPE: soa,ns,a,aaaa,cname,mx,txt,ptr,srv,any


ntpd [−dnqNwl] [−I IFACE ] [−S PROG ] [−k KEYFILE ] [−p [keyno:N:]PEER]...

NTP client/server

−d[d] Verbose
−n Run in foreground
−q Quit after clock is set
−N Run at high priority
−w Do not set time (only query peers), implies −n
−S PROG Run PROG after stepping time, stratum change, and every 11 min
−k FILE Key file (ntp.keys compatible)
−p [keyno:NUM:]PEER
Obtain time from PEER (may be repeated)
Use key NUM for authentication
If −p is not given, 'server HOST' lines
from /etc/ntp.conf are used
−l Also run as server on port 123
−I IFACE Bind server to IFACE, implies −l


od [−abcdfhilovxs] [−t TYPE ] [−A RADIX ] [−N SIZE ] [−j SKIP ] [−S MINSTR ] [−w WIDTH ] [ FILE ]...

Print FILEs (or stdin) unambiguously, as octal bytes by default


openvt [−c N] [−sw] [ PROG ARGS ]

Start PROG on a new virtual terminal

−c N Use specified VT
−s Switch to the VT
−w Wait for PROG to exit


partprobe DEVICE...

Ask kernel to rescan partition table


passwd [−a ALG ] [−dlu] [ USER ]

Change USER ’s password (default: current user)

−a ALG des,md5,sha256/512 (default sha512)
−d Set password to ''
−l Lock (disable) account
−u Unlock (enable) account


paste [−d LIST ] [−s] [ FILE ]...

Paste lines from each input file, separated with tab

−d LIST Use delimiters from LIST, not tab
−s Serial: one file at a time


pgrep [−flanovx] [−s SID|−P PPID|PATTERN]

Display process(es) selected by regex PATTERN

−l Show command name too
−a Show command line 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
−u EUID Match against effective UID
−U UID Match against UID


pidof [−s] [−o PID ] [ NAME ]...

List PIDs of all processes with names that match NAMEs

−s Show only one PID
−o PID Omit given pid
Use %PPID to omit pid of pidof's parent




−4,−6 Force IP or IPv6 name resolution
−c CNT Send only CNT pings
−s SIZE Send SIZE data bytes in packets (default 56)
−i SECS Interval
−A Ping as soon as reply is recevied
−t TTL Set TTL
−I IFACE/IP Source interface or IP address
−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 display output at start/finish
−p HEXBYTE Payload pattern


ping6 [ OPTIONS ] HOST


−c CNT Send only CNT pings
−s SIZE Send SIZE data bytes in packets (default 56)
−i SECS Interval
−A Ping as soon as reply is recevied
−I IFACE/IP Source interface or IP address
−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 display output at start/finish
−p HEXBYTE Payload pattern


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] [−xfvno] [−s SID|−P PPID|PATTERN]

Send signal to processes selected by regex PATTERN

−l List all signals
−x Match whole name (not substring)
−f Match against entire command line
−s SID Match session ID (0 for current)
−P PPID Match parent process ID
−v Negate the match
−n Signal the newest process only
−o Signal the oldest process only
−u EUID Match against effective UID
−U UID Match against UID


pmap [−xq] PID...

Display process memory usage

−x Show details
−q Quiet


poweroff [−d DELAY ] [−nf]

Halt and shut off power

−d SEC Delay interval
−n Do not sync
−f Force (don't go through init)


printenv [ VARIABLE ]...

Print environment VARIABLEs. If no VARIABLE specified, print all.


printf FORMAT [ ARG ]...

Format and print ARG (s) according to FORMAT (a−la C printf)


ps [−o COL1 ,COL2=HEADER] [−T]

Show list of processes

−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 HOST, print all open ports

−c Show closed ports too
−b Show blocked ports too
−p PORT Scan from this port (default 1)
−P PORT Scan up to this port (default 1024)
−t MS Timeout (default 5000 ms)
−T MS Minimum rtt (default 5 ms)


pstree [−p] [PID|USER]

Display process tree, optionally start from USER or PID

−p Show pids



Print the full filename of the current working directory


pwdx PID...

Show current directory for PIDs


raidautorun DEVICE

Tell the kernel to automatically search and start RAID arrays


rdate [−s/−p] HOST

Set and print time from HOST using RFC 868

−s Only set system time
−p Only print time



Print the device node associated with the filesystem mounted at ’/’


readahead [ FILE ]...

Preload FILEs to RAM


readlink [−fnv] FILE

Display the value of a symlink

−f Canonicalize by following all symlinks
−n Don't add newline
−v Verbose


realpath FILE...

Print absolute pathnames of FILEs


reboot [−d DELAY ] [−nf]

Reboot the system

−d SEC Delay interval
−n Do not sync
−f Force (don't go through init)


reformime [ OPTIONS ]

Parse MIME-encoded message on stdin

−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


remove-shell SHELL...

Remove SHELLs from /etc/shells


renice [−n] PRIORITY [[−p|g|u] ID... ]...

Change scheduling priority of a running process

−n Add PRIORITY to current nice value
Without −n, nice value is set to PRIORITY
−p Process ids (default)
−g Process group ids
−u Process user names



Reset the screen



Resize the screen


rev [ FILE ]...

Reverse lines of FILE



Enable/disable wireless devices


list [INDEX|TYPE] List current state
block INDEX|TYPE Disable device
unblock INDEX|TYPE Enable device
TYPE: all, wlan(wifi), bluetooth, uwb(ultrawideband),
wimax, wwan, gps, fm


rm [−irf] FILE...

Remove (unlink) FILEs

−i Always prompt before removing
−f Never prompt
−R,−r Recurse


rmdir [−p] DIRECTORY...

Remove DIRECTORY if it is empty

−p Include parents


rmmod [−wfa] [ MODULE ]...

Unload kernel modules

−w Wait until the module is no longer used
−f Force unload
−a Remove all unused modules (recursively)


route [−ne] [−A inet[6]] [{add|del} [−net|−host] TARGET [netmask MASK ]

[gw GATEWAY ] [metric N] [mss BYTES ] [window BYTES ] [reject] [ IFACE ]]

Show or edit kernel routing tables

−n Don't resolve names
−e Display other/more information
−A inet[6] Select address family


run-parts [−a ARG ]... [−u UMASK ] [−−reverse] [−−test] [−−exit−on−error] DIRECTORY

Run a bunch of scripts in DIRECTORY

−a ARG Pass ARG as argument to scripts
−u UMASK Set UMASK before running scripts
−−reverse Reverse execution order
−−test Dry run
−−exit−on−error Exit if a script exits with non−zero


sed [−i[ SFX ]] [−nrE] [−f FILE ]... [−e CMD ]... [ FILE ]... or: sed [−i[ SFX ]] [−nrE] CMD [ FILE ]...

−e CMD Add CMD to sed commands to be executed
−f FILE Add FILE contents to sed commands to be executed
−i[SFX] Edit files in−place (otherwise write to stdout)
Optionally back files up, appending SFX
−n Suppress automatic printing of pattern space
−r,−E Use extended regex syntax

If no −e or −f, the first non-option argument is the sed command string. Remaining arguments are input files (stdin if none).


sendmail [−tv] [−f SENDER ] [−amLOGIN 4<user_pass.txt | −auUSER −apPASS]


Read email from stdin and send it

Standard options:

−t Read additional recipients from message body
−f SENDER For use in MAIL FROM:<sender>. Can be empty string
Default: −auUSER, or username of current UID
−o OPTIONS Various options. −oi implied, others are ignored
−i −oi synonym, implied and ignored

Busybox specific options:

−v Verbose
−w SECS Network timeout
−H 'PROG ARGS' Run connection helper. Examples:
openssl s_client −quiet −tls1 −starttls smtp −connect smtp.gmail.com:25
openssl s_client −quiet −tls1 −connect smtp.gmail.com:465
$SMTP_ANTISPAM_DELAY: seconds to wait after helper connect
−S HOST[:PORT] Server (default $SMTPHOST or
−amLOGIN Log in using AUTH LOGIN
(−amCRAM−MD5 not supported)
−auUSER Username for AUTH
−apPASS Password for AUTH

If no −a options are given, authentication is not done. If −amLOGIN is given but no −au/−ap, user/password is read from fd #4. Other options are silently ignored; −oi is implied. Use makemime to create emails with attachments.


seq [−w] [−s SEP ] [ FIRST [ INC ]] LAST

Print numbers from FIRST to LAST, in steps of INC. FIRST, INC default to 1.

−w Pad to last with leading zeros
−s SEP String separator


setconsole [−r] [ DEVICE ]

Make writes to /dev/console appear on DEVICE (default: /dev/tty). Does not redirect kernel log output or reads from /dev/console.

−r Reset: writes to /dev/console go to kernel log tty(s)


setfont [−m MAPFILE ] [−C TTY ] FILE

Load a console font

−m MAPFILE Load console screen map
−C TTY Affect TTY instead of /dev/tty


setkeycodes { SCANCODE KEYCODE }...

Modify kernel’s scancode-to-keycode map, allowing unusual keyboards to generate usable keycodes.

SCANCODE is either xx or e0xx (hexadecimal), KEYCODE is decimal.


setlogcons [N]

Pin kernel output to VT console N. Default:0 (do not pin)



Run PROG with different privilege settings


Show current capabilities −−nnp,−−no−new−privs

Ignore setuid/setgid bits and file capabilities −−inh−caps CAP,CAP

Set inheritable capabilities −−ambient−caps CAP,CAP

Set ambient capabilities


setserial [−abGvz] { DEVICE [ PARAMETER [ ARG ]]... | −g DEVICE... }

Print or set serial port parameters

−a Print all
−b Print summary
−G Print as setserial PARAMETERs
−v Verbose
−z Zero out serial flags before setting
−g All args are device names

PARAMETERs: (* = takes ARG, ^ = can be turned off by preceding ^)

*port, *irq, *divisor, *uart, *baud_base, *close_delay, *closing_wait,

^fourport, ^auto_irq, ^skip_test, ^sak, ^session_lockout, ^pgrp_lockout,

^callout_nohup, ^split_termios, ^hup_notify, ^low_latency, autoconfig,

spd_normal, spd_hi, spd_vhi, spd_shi, spd_warp, spd_cust ARG for uart:

unknown, 8250, 16450, 16550, 16550A, Cirrus, 16650, 16650V2, 16750,
16950, 16954, 16654, 16850, RSA, NS16550A, XSCALE, RM9000, OCTEON, AR7,


setsid [−c] PROG ARGS

Run PROG in a new session. PROG will have no controlling terminal and will not be affected by keyboard signals (^C etc).

−c Set controlling terminal to stdin


sh [−il] [−|+Cabefmnuvx] [−|+o OPT ]... [−c ’ SCRIPT ’ [ ARG0 ARGS ] | FILE ARGS | −s ARGS ]

Unix shell interpreter


sha1sum [−c[sw]] [ FILE ]...

Print or check SHA1 checksums

−c Check sums against list in FILEs
−s Don't output anything, status code shows success
−w Warn about improperly formatted checksum lines


sha256sum [−c[sw]] [ FILE ]...

Print or check SHA256 checksums

−c Check sums against list in FILEs
−s Don't output anything, status code shows success
−w Warn about improperly formatted checksum lines


sha3sum [−c[sw]] [−a BITS ] [ FILE ]...

Print or check SHA3 checksums

−c Check sums against list in FILEs
−s Don't output anything, status code shows success
−w Warn about improperly formatted checksum lines
−a BITS 224 (default), 256, 384, 512


sha512sum [−c[sw]] [ FILE ]...

Print or check SHA512 checksums

−c Check sums against list in FILEs
−s Don't output anything, status code shows success
−w Warn about improperly formatted checksum lines


showkey [−a | −k | −s]

Show keys pressed

−a Display decimal/octal/hex values of the keys
−k Display interpreted keycodes (default)
−s Display raw scan−codes


shred [−fuz] [−n N] [−s SIZE ] FILE...

Overwrite/delete FILEs

−f Chmod to ensure writability
−s SIZE Size to write
−n N Overwrite N times (default 3)
−z Final overwrite with zeros
−u Remove file


shuf [−n NUM ] [−o FILE ] [−z] [ FILE | −e [ ARG... ] | −i L−H]

Randomly permute lines

−n NUM Output at most NUM lines
−o FILE Write to FILE, not standard output
−z NUL terminated output
−e Treat ARGs as lines
−i L−H Treat numbers L−H as lines


slattach [−ehmLF] [−c SCRIPT ] [−s BAUD ] [−p PROTOCOL ] SERIAL_DEVICE

Configure serial line as SLIP network interface

−p PROT Protocol: slip, cslip (default), slip6, clisp6, adaptive
−s BAUD Line speed
−e Exit after initialization
−h Exit if carrier is lost (else never exits)
−c PROG Run PROG on carrier loss
−m Do NOT set raw 8bit 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


sort [−nrugMcszbdfiokt] [−o FILE ] [−k START[.OFS][ OPTS ][,END[.OFS][ OPTS ]] [−t CHAR ] [ FILE ]...

Sort lines of text

−o FILE Output to FILE
−c Check whether input is sorted
−b Ignore leading blanks
−f Ignore case
−i Ignore unprintable characters
−d Dictionary order (blank or alphanumeric only)
−n Sort numbers
−g General numerical sort
−M Sort month
−V Sort version
−t CHAR Field separator
−k N[,M] Sort by Nth field
−r Reverse sort order
−s Stable (don't sort ties alphabetically)
−u Suppress duplicate lines
−z NUL terminated input and output


split [ OPTIONS ] [ INPUT [ PREFIX ]]

−b N[k|m] Split by N (kilo|mega)bytes
−l N Split by N lines
−a N Use N letters as suffix


stat [−ltf] [−c FMT ] FILE...

Display file (default) or filesystem status

−c FMT Use the specified format
−f Display filesystem status
−L Follow links
−t Terse display

FMT sequences for files:

%a Access rights in octal
%A Access rights in human readable form
%b Number of blocks allocated (see %B)
%B 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
%G Group name
%h Number of hard links
%i Inode number
%n File name
%N File name, with −> TARGET 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
%U User name
%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

FMT sequences for file systems:

%a Free blocks available to non−superuser
%b Total data blocks
%c Total file nodes
%d Free file nodes
%f Free blocks
%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 [−fo] [−t o|d|x] [−n LEN ] [ FILE ]...

Display printable strings in a binary file

−f Precede strings with filenames
−o Precede strings with octal offsets
−t o|d|x Precede strings with offsets in base 8/10/16
−n LEN At least LEN characters form a string (default 4)


stty [−a|g] [−F DEVICE ] [ SETTING ]...

Without arguments, prints baud rate, line discipline, and deviations from stty sane

−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 [−lmp] [−s SH ] [−] [ USER [ FILE ARGS | −c ’ CMD ’ [ ARG0 ARGS ]]]

Run shell under USER (by default, root)

−,−l Clear environment, go to home dir, run shell as login shell
−p,−m Do not set new $HOME, $SHELL, $USER, $LOGNAME
−c CMD Command to pass to 'sh −c'
−s SH Shell to use instead of user's default


sum [−rs] [ FILE ]...

Checksum and count the blocks in a file

−r Use BSD sum algorithm (1K blocks)
−s Use System V sum algorithm (512byte blocks)


swapoff [−a] [ DEVICE ]

Stop swapping on DEVICE

−a Stop swapping on all swap devices


swapon [−a] [−e] [−d[ POL ]] [−p PRI ] [ DEVICE ]

Start swapping on DEVICE

−a Start swapping on all swap devices
−d[POL] Discard blocks at swapon (POL=once),
as freed (POL=pages), or both (POL omitted)
−e Silently skip devices that do not exist
−p PRI Set swap device priority


switch_root [−c CONSOLE_DEV ] 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.

−c DEV Reopen stdio to DEV after switch


sync [−df] [ FILE ]...

Write all buffered blocks (in FILEs) to disk


Avoid syncing metadata


Sync filesystems underlying FILEs


sysctl [−enq] { −a | −p [ FILE ]... | [−w] [KEY[=VALUE]]... }

Show/set kernel parameters

−e Don't warn about unknown keys
−n Don't show key names
−q Quiet
−a Show all values
−p Set values from FILEs (default /etc/sysctl.conf)
−w Set values


syslogd [ OPTIONS ]

System logging utility

−n Run in foreground
−R HOST[:PORT] Log to HOST:PORT (default PORT:514)
−L Log locally and via network (default is network only if −R)
−C[size_kb] Log to shared mem buffer (use logread to read it)
−K Log to kernel printk buffer (use dmesg to read it)
−O FILE Log to FILE (default: /var/log/messages, stdout if −)
−s SIZE Max size (KB) before rotation (default 200KB, 0=off)
−b N N rotated logs to keep (default 1, max 99, 0=purge)
−l N Log only messages more urgent than prio N (1−8)
−S Smaller output
−t Strip client−generated timestamps
−D Drop duplicates
−f FILE Use FILE as config (default:/etc/syslog.conf)


tac [ FILE ]...

Concatenate FILEs and print them in reverse


tail [ OPTIONS ] [ FILE ]...

Print last 10 lines of FILEs (or stdin) to. With more than one FILE, precede each with a filename header.

−c [+]N[bkm] Print last N bytes
−n N[bkm] Print last N lines
−n +N[bkm] Start on Nth line and print the rest
(b:*512 k:*1024 m:*1024^2)
−q Never print headers
−v Always print headers
−f Print data as file grows
−F Same as −f, but keep retrying
−s SECONDS Wait SECONDS between reads with −f


tar c|x|t [−ZzJjahmvokO] [−f TARFILE ] [−C DIR ] [−T FILE ] [−X FILE ] [ LONGOPT ]... [ FILE ]...

Create, extract, or list files from a tar file

c Create
x Extract
t List
−f FILE Name of TARFILE ('−' for stdin/out)
−C DIR Change to DIR before operation
−v Verbose
−O Extract to stdout
−m Don't restore mtime
−o Don't restore user:group
−k Don't replace existing files
−Z (De)compress using compress
−z (De)compress using gzip
−J (De)compress using xz
−j (De)compress using bzip2
−−lzma (De)compress using lzma
−a (De)compress based on extension
−h Follow symlinks
−T FILE File with names to include
−X FILE File with glob patterns to exclude
−−exclude PATTERN Glob pattern to exclude
−−overwrite Replace existing files
−−strip−components NUM NUM of leading components to strip
−−no−recursion Don't descend in directories
−−numeric−owner Use numeric user:group
−−no−same−permissions Don't restore access permissions


tee [−ai] [ FILE ]...

Copy stdin to each FILE, and also to stdout

−a Append to the given FILEs, don't overwrite
−i Ignore interrupt signals (SIGINT)


time [−vpa] [−o FILE ] PROG ARGS

Run PROG, display resource usage when it exits

−v Verbose
−p POSIX output format
−f FMT Custom format
−o FILE Write result to FILE
−a Append (else overwrite)


timeout [−s SIG ] [−k KILL_SECS ] SECS PROG ARGS

Run PROG. Send SIG to it if it is not gone in SECS seconds. Default SIG: TERM .If it still exists in KILL_SECS seconds, send KILL.


top [−bmH] [−n COUNT ] [−d SECONDS ]

Show a view of process activity in real time. Read the status of all processes from /proc each SECONDS and show a screenful of them. Keys:

N/M/P/T: show CPU usage, sort by pid/mem/cpu/time
S: show memory
R: reverse sort
H: toggle threads, 1: toggle SMP
Q,^C: exit
−b Batch mode
−n N Exit after N iterations
−d SEC Delay between updates
−m Same as 's' key
−H Show threads


touch [−cham] [−d DATE ] [−t DATE ] [−r FILE ] FILE...

Update mtime of FILEs

−c Don't create files
−h Don't follow links
−a Change only atime
−m Change only mtime
−d DT Date/time to use
−t DT Date/time to use
−r FILE Use FILE's date/time


tr [−cds] STRING1 [ STRING2 ]

Translate, squeeze, or delete characters from stdin, writing to stdout

−c Take complement of STRING1
−d Delete input characters coded STRING1
−s Squeeze multiple output characters of STRING2 into one character


traceroute [−46IFlnrv] [−f 1ST_TTL] [−m MAXTTL ] [−q PROBES ] [−p PORT ]

[−t TOS ] [−w WAIT_SEC ] [−s SRC_IP ] [−i IFACE ]


Trace the route to HOST

−4,−6 Force IP or IPv6 name resolution
−F Set don't fragment bit
−I Use ICMP ECHO instead of UDP datagrams
−l Display TTL value of the returned packet
−n Print numeric addresses
−r Bypass routing tables, send directly to HOST
−v Verbose
−f N First number of hops (default 1)
−m N Max number of hops
−q N Number of probes per hop (default 3)
−p N Base UDP port number used in probes
(default 33434)
−s IP Source address
−i IFACE Source interface
−t N Type−of−service in probe packets (default 0)
−w SEC Wait for a response (default 3)
−z MSEC Wait before each send


traceroute6 [−Inrv] [−f 1ST_TTL] [−m MAXTTL ] [−q PROBES ] [−p PORT ]

[−t TOS ] [−w WAIT_SEC ] [−s SRC_IP ] [−i IFACE ]


Trace the route to HOST

−I Use ICMP ECHO instead of UDP datagrams
−n Print numeric addresses
−r Bypass routing tables, send directly to HOST
−v Verbose
−f N First number of hops (default 1)
−m N Max number of hops
−q N Number of probes per hop (default 3)
−p N Base UDP port number used in probes
(default 33434)
−s IP Source address
−i IFACE Source interface
−t N Type−of−service in probe packets (default 0)
−w SEC Wait for a response (default 3)
−z MSEC Wait before each send


truncate [−c] −s SIZE FILE...

Truncate FILEs to SIZE

−c Do not create files



Print file name of stdin’s terminal


ttysize [w] [h]

Print dimensions of stdin tty, or 80x24


tunctl [−f DEVICE ] [−t NAME | −d NAME ] [−u USER ] [−g GRP ] [−b]

Create or delete TUN/TAP interfaces

−f DEV TUN device (default /dev/net/tun)
−t NAME Create iface (default: tapN)
−d NAME Delete iface
−u USER Set iface owner
−g GRP Set iface group
−b Brief output


udhcpc [−fbqRB] [−a[ MSEC ]] [−t N] [−T SEC ] [−A SEC|−n]

[−i IFACE ] [−s PROG ] [−p PIDFILE ]

[−oC] [−r IP ] [−V VENDOR ] [−F NAME ] [−x OPT:VAL ]... [−O OPT ]...

−i IFACE Interface to use (default eth0)
−s PROG Run PROG at DHCP events (default /usr/share/udhcpc/default.script)
−p FILE Create pidfile
−B Request broadcast replies
−t N Send up to N discover packets (default 3)
−T SEC Pause between packets (default 5)
−A SEC Wait if lease is not obtained (default 20)
−b Background if lease is not obtained
−n Exit if lease is not obtained
−q Exit after obtaining lease
−R Release IP on exit
−f Run in foreground
−S Log to syslog too
−a[MSEC] Validate offered address with ARP ping
−r IP Request this IP address
−o Don't request any options (unless −O is given)
−O OPT Request option OPT from server (cumulative)
−x OPT:VAL Include option OPT in sent packets (cumulative)
Examples of string, numeric, and hex byte opts:
−x hostname:bbox − option 12
−x lease:3600 − option 51 (lease time)
−x 0x3d:0100BEEFC0FFEE − option 61 (client id)
−x 14:'"dumpfile"' − option 14 (shell−quoted)
−F NAME Ask server to update DNS mapping for NAME
−V VENDOR Vendor identifier (default 'udhcp VERSION')
−C Don't send MAC as client identifier
USR1 Renew lease
USR2 Release lease


udhcpc6 [−fbqR] [−t N] [−T SEC ] [−A SEC|−n] [−i IFACE ] [−s PROG ]

[−p PIDFILE ] [−ldo] [−r IPv6] [−x OPT:VAL ]... [−O OPT ]...

−i IFACE Interface to use (default eth0)
−p FILE Create pidfile
−s PROG Run PROG at DHCP events (default /usr/share/udhcpc/default.script)
−B Request broadcast replies
−t N Send up to N discover packets
−T SEC Pause between packets (default 5)
−A SEC Wait if lease is not obtained (default 20)
−b Background if lease is not obtained
−n Exit if lease is not obtained
−q Exit after obtaining lease
−R Release IP on exit
−f Run in foreground
−S Log to syslog too
−l Send 'information request' instead of 'solicit'
(used for servers which do not assign IPv6 addresses)
−r IPv6 Request this address ('no' to not request any IP)
−d Request prefix
−o Don't request any options (unless −O is given)
−O OPT Request option OPT from server (cumulative)
−x OPT:VAL Include option OPT in sent packets (cumulative)
Examples of string, numeric, and hex byte opts:
−x hostname:bbox − option 12
−x lease:3600 − option 51 (lease time)
−x 0x3d:0100BEEFC0FFEE − option 61 (client id)
−x 14:'"dumpfile"' − option 14 (shell−quoted)
USR1 Renew lease
USR2 Release lease



Unmount filesystems

−a Unmount all filesystems
−r Remount devices 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
−t FSTYPE[,...] Unmount only these filesystem type(s)


uname [−amnrspvio]

Print system information

−a Print all
−m Machine (hardware) type
−n Hostname
−r Kernel release
−s Kernel name (default)
−p Processor type
−v Kernel version
−i Hardware platform
−o OS name


unexpand [−fa][−t N] [ FILE ]...

Convert spaces to tabs, writing to stdout

−a Convert all blanks
−f Convert only leading blanks
−t N Tabstops every N chars


uniq [−cduiz] [−f,s,w N] [ FILE [ OUTFILE ]]

Discard duplicate lines

−c Prefix lines by the number of occurrences
−d Only print duplicate lines
−u Only print unique lines
−i Ignore case
−z NUL terminated output
−f N Skip first N fields
−s N Skip first N chars (after any skipped fields)
−w N Compare N characters in line


unix2dos [−ud] [ FILE ]

Convert FILE in-place from Unix to DOS format. When no file is given, use stdin/stdout.

−u dos2unix
−d unix2dos


unlink FILE

Delete FILE by calling unlink()


unlzma [−cfk] [ FILE ]...

Decompress FILEs (or stdin)

−c Write to stdout
−f Force
−k Keep input files
−t Test integrity


unlzop [−cfUvF] [ FILE ]...

−c Write to stdout
−f Force
−U Delete input files
−t Test integrity
−v Verbose
−F Don't verify checksum


unshare [ OPTIONS ] [ PROG ARGS ]

−m,−−mount[=FILE] Unshare mount namespace
−u,−−uts[=FILE] Unshare UTS namespace (hostname etc.)
−i,−−ipc[=FILE] Unshare System V IPC namespace
−n,−−net[=FILE] Unshare network namespace
−p,−−pid[=FILE] Unshare PID namespace
−U,−−user[=FILE] Unshare user namespace
−f Fork before execing PROG
−r Map current user to root (implies −U)
−−mount−proc[=DIR] Mount /proc filesystem first (implies −m)
−−propagation slave|shared|private|unchanged
Modify mount propagation in mount namespace
−−setgroups allow|deny Control the setgroups syscall in user namespaces


unxz [−cfk] [ FILE ]...

Decompress FILEs (or stdin)

−c Write to stdout
−f Force
−k Keep input files
−t Test integrity


unzip [−lnojpq] FILE[.zip] [ FILE ]... [−x FILE ]... [−d DIR ]

Extract FILEs from ZIP archive

−l List contents (with −q for short form)
−n Never overwrite files (default: ask)
−o Overwrite
−j Do not restore paths
−p Write to stdout
−t Test
−q Quiet
−x FILE Exclude FILEs
−d DIR Extract into DIR



Display the time since the last boot


usleep N

Pause for N microseconds


uudecode [−o OUTFILE ] [ INFILE ]

Uudecode a file Finds OUTFILE in uuencoded source unless −o is given


uuencode [−m] [ FILE ] STORED_FILENAME

Uuencode FILE (or stdin) to stdout

−m Use base64 encoding per RFC1521



Create and remove virtual ethernet devices

set_flag IFACE 0|1 VLAN_QOS
set_name_type NAME_TYPE


vi [−c CMD ] [−R] [−H] [ FILE ]...


−c CMD Initial command to run ($EXINIT and ~/.exrc also available)
−R Read−only
−H List available features


vlock [−a]

Lock a virtual terminal. A password is required to unlock.

−a Lock all VTs


volname [ DEVICE ]

Show CD volume name of the DEVICE (default /dev/cdrom)


watch [−n SEC ] [−t] PROG ARGS

Run PROG periodically

−n SEC Period (default 2)
−t Don't print header


watchdog [−t N[ms]] [−T N[ms]] [−F] DEV

Periodically write to watchdog device DEV

−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 [−cmlwL] [ FILE ]...

Count lines, words, and bytes for FILEs (or stdin)

−c Count bytes
−m Count characters
−l Count newlines
−w Count words
−L Print longest line length


wget [−cqS] [−−spider] [−O FILE ] [−o LOGFILE ] [−−header STR ]

[−−post−data STR | −−post−file FILE ] [−Y on/off]

[−P DIR ] [−U AGENT ] [−T SEC ] URL...

Retrieve files via HTTP or FTP

−−spider Only check URL existence: $? is 0 if exists
−−header STR Add STR (of form 'header: value') to headers
−−post−data STR Send STR using POST method
−−post−file FILE Send FILE using POST method
−c Continue retrieval of aborted transfer
−q Quiet
−P DIR Save to DIR (default .)
−S Show server response
−T SEC Network read timeout is SEC seconds
−O FILE Save to FILE ('−' for stdout)
−o LOGFILE Log messages to FILE
−U STR Use STR for User−Agent header
−Y on/off Use proxy


which [−a] COMMAND...


−a Show all matches


who [−aH]

Show who is logged on

−a Show all
−H Print column headers



Print the user name associated with the current effective user id


whois [−i] [−h SERVER ] [−p PORT ] NAME...

Query WHOIS info about NAME

−i Show redirect results too
−h,−p Server to query


xargs [ OPTIONS ] [ PROG ARGS ]

Run PROG on every item given by stdin

−0 NUL terminated input
−a FILE Read from FILE instead of stdin
−r Don't run command if input is empty
−t Print the command on stderr before execution
−p Ask user whether to run each command
−E STR,−e[STR] STR stops input processing
−I STR Replace STR within PROG ARGS with input line
−n N Pass no more than N args to PROG
−s N Pass command line of no more than N bytes
−P N Run up to N PROGs in parallel
−x Exit if size is exceeded


xxd [−pri] [−g N] [−c N] [−n LEN ] [−s OFS ] [−o OFS ] [ FILE ]

Hex dump FILE (or stdin)

−g N Bytes per group
−c N Bytes per line
−p Show only hex bytes, assumes −c30
−i C include file style
−l LENGTH Show only first LENGTH bytes
−s OFFSET Skip OFFSET bytes
−o OFFSET Add OFFSET to displayed offset
−r Reverse (with −p, assumes no offsets in input)


xzcat [ FILE ]...

Decompress to stdout


yes [ STRING ]

Repeatedly print a line with STRING, or ’y’


zcat [ FILE ]...

Decompress to stdout


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 protected]>


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 protected]>


Erik Andersen <[email protected]>

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 protected]>

rpm2cpio, unzip, get_header_cpio, read_gz interface, rpm

Jeff Angielski <[email protected]>

ftpput, ftpget

Edward Betts <[email protected]>

expr, hostid, logname, whoami

John Beppu <[email protected]>

du, nslookup, sort

Brian Candler <[email protected]>


Randolph Chung <[email protected]>

fbset, ping, hostname

Dave Cinege <[email protected]>

more(v2), makedevs, dutmp, modularization, auto links file,
various fixes, Linux Router Project maintenance

Jordan Crouse <[email protected]>


Magnus Damm <[email protected]>

tftp client insmod powerpc support

Larry Doolittle <[email protected]>

pristine source directory compilation, lots of patches and fixes.

Glenn Engel <[email protected]>


Gennady Feldman <[email protected]>

Sysklogd (single threaded syslogd, IPC Circular buffer support,
logread), various fixes.

Karl M. Hegbloom <[email protected]>

cp_mv.c, the test suite, various fixes to utility.c, &c.

Daniel Jacobowitz <[email protected]>


Matt Kraai <[email protected]>

documentation, bugfixes, test suite

Stephan Linz <linz@li−pro.net>

ipcalc, Red Hat equivalence

John Lombardo <[email protected]>


Glenn McGrath <[email protected]>

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 protected]>

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 protected]>

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 protected]>

Original author of BusyBox in 1995, 1996. Some of his code can
still be found hiding here and there...

Tim Riker <[email protected]>

bug fixes, member of fan club

Kent Robotti <[email protected]>

reset, tons and tons of bug reports and patches.

Chip Rosenthal <[email protected]>, <[email protected]>

wget − Contributed by permission of Covad Communications

Pavel Roskin <[email protected]>

Lots of bugs fixes and patches.

Gyepi Sam <gyepi@praxis−sw.com>

Remote logging feature for syslogd

Linus Torvalds <[email protected]>

mkswap, fsck.minix, mkfs.minix

Mark Whitley <[email protected]>

grep, sed, cut, xargs(previous),
style−guide, new−applet−HOWTO, bug fixes, etc.

Charles P. Wright <[email protected]>

gzip, mini−netcat(nc)

Enrique Zanardi <[email protected]>

tarcat (since removed), loadkmap, various fixes, Debian maintenance

Tito Ragusa <[email protected]>

devfsd and size optimizations in strings, openvt and deallocvt.

Paul Fox <[email protected]>

vi editing mode for ash, various other patches/fixes

Roberto A. Foglietta <[email protected]>

port: dnsd

Bernhard Reutner-Fischer <[email protected]>


Mike Frysinger <[email protected]>

initial e2fsprogs, printenv, setarch, sum, misc

Jie Zhang <[email protected]>

fixed two bugs in msh and hush (exitcode of killed processes)

Updated 2023-02-15 - jenkler.se | uex.se