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Manual Reference Pages  - BUSYBOX (1)


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:

        [, [[, adjtimex, ar, arp, arping, ash, awk, basename, blockdev,
        brctl, bunzip2, bzcat, bzip2, cal, cat, chgrp, chmod, chown, chroot,
        chvt, clear, cmp, cp, cpio, cttyhack, cut, date, dc, dd, deallocvt,
        depmod, df, diff, dirname, dmesg, dnsdomainname, dos2unix, du,
        dumpkmap, dumpleases, echo, egrep, env, expand, expr, false, fgrep,
        find, fold, free, freeramdisk, ftpget, ftpput, getopt, getty, grep,
        groups, gunzip, gzip, halt, head, hexdump, hostid, hostname, httpd,
        hwclock, id, ifconfig, init, insmod, ionice, ip, ipcalc, kill,
        killall, klogd, last, less, ln, loadfont, loadkmap, logger, login,
        logname, logread, losetup, ls, lsmod, lzcat, lzma, md5sum, mdev,
        microcom, mkdir, mkfifo, mknod, mkswap, mktemp, modinfo, modprobe,
        more, mount, mt, mv, nameif, nc, netstat, nslookup, od, openvt,
        patch, pidof, ping, ping6, pivot_root, poweroff, printf, ps, pwd,
        rdate, readlink, realpath, reboot, renice, reset, rev, rm, rmdir,
        rmmod, route, rpm, rpm2cpio, run-parts, sed, seq, setkeycodes,
        setsid, sh, sha1sum, sha256sum, sha512sum, sleep, sort,
        start-stop-daemon, stat, strings, stty, swapoff, swapon,
        switch_root, sync, sysctl, syslogd, tac, tail, tar, taskset, tee,
        telnet, test, tftp, time, timeout, top, touch, tr, traceroute,
        traceroute6, true, tty, udhcpc, udhcpd, umount, uname, uncompress,
        unexpand, uniq, unix2dos, unlzma, unxz, unzip, uptime, usleep,
        uudecode, uuencode, vconfig, vi, watch, watchdog, wc, wget, which,
        who, whoami, xargs, xz, xzcat, yes, zcat


adjtimex adjtimex [-q] [-o OFF] [-f FREQ] [-p TCONST] [-t TICK]

Read and optionally set system timebase parameters. See adjtimex(2)

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

ar ar [-o] [-v] [-p] [-t] [-x] ARCHIVE FILES

Extract or list FILES from an ar archive

        -o      Preserve original dates
        -p      Extract to stdout
        -t      List
        -x      Extract
        -v      Verbose

arp 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
        -s              Set new ARP entry
        -d              Delete a specified entry
        -v              Verbose
        -n              Dont resolve names
        -i IF           Network interface
        -D              Read <hwaddr> from given device
        -A,-p AF        Protocol family
        -H HWTYPE       Hardware address type

arping 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, dont 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, seconds
        -I IFACE        Interface to use (default eth0)
        -s SRC_IP       Sender IP address
        DST_IP          Target IP address

ash ash [-/+OPTIONS] [-/+o OPT]... [-c ’SCRIPT’ [ARG0 [ARGS]] / FILE [ARGS]]

Unix shell interpreter


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

basename basename FILE [SUFFIX]

Strip directory path and .SUFFIX from FILE

blockdev blockdev OPTION BLOCKDEV

        --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
        --flushbufs     Flush buffers
        --rereadpt      Reread partition table


Manage ethernet bridges


        addbr BRIDGE            Create BRIDGE
        delbr BRIDGE            Delete BRIDGE
        addif BRIDGE IFACE      Add IFACE to BRIDGE
        delif BRIDGE IFACE      Delete IFACE from BRIDGE

bunzip2 bunzip2 [-cf] [FILE]...

Decompress FILEs (or stdin)

        -c      Write to stdout
        -f      Force

bzcat bzcat FILE

Decompress to stdout

bzip2 bzip2 [OPTIONS] [FILE]...

Compress FILEs (or stdin) with bzip2 algorithm

        -1..9   Compression level
        -d      Decompress
        -c      Write to stdout
        -f      Force

cal cal [-jy] [[MONTH] YEAR]

Display a calendar

        -j      Use julian dates
        -y      Display the entire year

cat cat [FILE]...

Concatenate FILEs and print them to stdout

chgrp chgrp [-RhLHPcvf]... GROUP FILE...

Change the group membership of each FILE to GROUP

        -R      Recurse
        -h      Affect symlinks instead of symlink targets
        -L      Traverse all symlinks to directories
        -H      Traverse symlinks on command line only
        -P      Dont traverse symlinks (default)
        -c      List changed files
        -v      Verbose
        -f      Hide errors

chmod 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

        -R      Recurse
        -c      List changed files
        -v      List all files
        -f      Hide errors

chown chown [-RhLHPcvf]... OWNER[<.|:>[GROUP]] FILE...

Change the owner and/or group of each FILE to OWNER and/or GROUP

        -R      Recurse
        -h      Affect symlinks instead of symlink targets
        -L      Traverse all symlinks to directories
        -H      Traverse symlinks on command line only
        -P      Dont traverse symlinks (default)
        -c      List changed files
        -v      List all files
        -f      Hide errors

chroot chroot NEWROOT [PROG ARGS]

Run PROG with root directory set to NEWROOT

chvt chvt N

Change the foreground virtual terminal to /dev/ttyN

clear clear

Clear screen

cmp cmp [-l] [-s] 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


Copy SOURCE(s) to DEST

        -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
        -l,-s   Create (sym)links

cpio cpio [-dmvu] [-F FILE] [-H newc] [-tio] [EXTR_FILE]...

Extract or list files from a cpio archive, or create an archive using file list on stdin

Main operation mode:

        -t      List
        -i      Extract EXTR_FILEs (or all)
        -o      Create (requires -H newc)
        -d      Make leading directories
        -m      Preserve mtime
        -v      Verbose
        -u      Overwrite
        -F FILE Input (-t,-i,-p) or output (-o) file
        -H newc Archive format

cttyhack cttyhack [PROG ARGS]

Give PROG a controlling tty if possible. Example for /etc/inittab (for busybox init):
        ::respawn:/bin/cttyhack /bin/sh Giving controlling tty to shell running with PID 1:
        $ exec cttyhack sh Starting interactive shell from boot shell script:

        setsid cttyhack sh

cut cut [OPTIONS] [FILE]...

Print selected fields from each input FILE to stdout

        -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 date [OPTIONS] [+FMT] [TIME]

Display time (using +FMT), or set time

        [-s,--set] TIME Set time to TIME
        -u,--utc        Work in UTC (dont convert to local time)
        -R,--rfc-2822   Output RFC-2822 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,--reference FILE     Display last modification time of FILE
        -d,--date TIME  Display TIME, not now
        -D FMT          Use FMT for -d TIME conversion

Recognized TIME formats:

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


Tiny RPN calculator. Operations: +, add, -, sub, *, mul, /, div, %, mod, and, or, not, eor, p - print top of the stack (without popping), f - print entire stack, o - pop the value and set output radix (must be 10, 16, 8 or 2). Examples: ’dc 2 2 add p’ -> 4, ’dc 8 8 * 2 2 + / p’ -> 16

dd 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

        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    Dont 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 deallocvt [N]

Deallocate unused virtual terminal /dev/ttyN

depmod 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 df [-Pkmhai] [-B SIZE] [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)
        -a      Show all filesystems
        -i      Inodes
        -B SIZE Blocksize

diff 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
        -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 dirname FILENAME

Strip non-directory suffix from FILENAME

dmesg dmesg [-c] [-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

dos2unix 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 du [-aHLdclsxhmk] [FILE]...

Summarize disk space used for each FILE and/or directory

        -a      Show file sizes too
        -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 dumpkmap > keymap

Print a binary keyboard translation table to stdout

dumpleases dumpleases [-r|-a] [-f LEASEFILE]

Display DHCP leases granted by udhcpd

        -f,--file=FILE  Lease file
        -r,--remaining  Show remaining time
        -a,--absolute   Show expiration time

echo echo [-neE] [ARG]...

Print the specified ARGs to stdout

        -n      Suppress trailing newline
        -e      Interpret backslash escapes (i.e., \t=tab)
        -E      Dont interpret backslash escapes (default)

env env [-iu] [-] [name=value]... [PROG ARGS]

Print the current environment or run PROG after setting up the specified environment

        -, -i   Start with an empty environment
        -u      Remove variable from the environment

expand expand [-i] [-t N] [FILE]...

Convert tabs to spaces, writing to stdout

        -i,--initial    Dont convert tabs after non blanks
        -t,--tabs=N     Tabstops every N chars

expr expr EXPRESSION

Print the value of EXPRESSION to stdout


        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.

false false

Return an exit code of FALSE (1)

find find [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’

        -follow         Follow symlinks
        -xdev           Dont descend directories on other filesystems
        -maxdepth N     Descend at most N levels. -maxdepth 0 applies
                        actions to command line arguments only
        -mindepth N     Dont act on first N levels
        -depth          Act on directory *after* traversing it


        ( ACTIONS )     Group actions for -o / -a
        ! ACT           Invert ACTs 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,...)
        -perm MASK      At least one mask bit (+MASK), all bits (-MASK),
                        or exactly MASK bits are set in files mode
        -mtime DAYS     mtime is greater than (+N), less than (-N),
                        or exactly 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 FILEs
        -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
        -prune          If current file is directory, dont 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

fold fold [-bs] [-w WIDTH] [FILE]...

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

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

free free [-b/k/m/g]

Display the amount of free and used system memory

freeramdisk freeramdisk DEVICE

Free all memory used by the specified ramdisk


Download a file via FTP

        -c,--continue           Continue previous transfer
        -v,--verbose            Verbose
        -u,--username USER      Username
        -p,--password PASS      Password
        -P,--port NUM           Port


Upload a file to a FTP server

        -v,--verbose            Verbose
        -u,--username USER      Username
        -p,--password PASS      Password
        -P,--port NUM           Port

getopt getopt [OPTIONS] [--] OPTSTRING PARAMS

        -a,--alternative                Allow long options starting with single -
        -l,--longoptions=LOPT[,...]     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                   Dont quote the output


O=‘getopt -l bb: — ab:c:: $@‘ || exit 1 eval set — $O while true; do
        case $1 in
        -a)     echo A; shift;;
        -b|--bb) echo B:’$2’; shift 2;;
        -c)     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 modems CONNECT status message
        -n              Dont prompt for login name
        -w              Wait for CR or LF before sending /etc/issue
        -i              Dont 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 grep [-HhnlLoqvsriwFEz] [-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 dont 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
        -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
        -z      Input is NUL terminated
        -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 groups [USER]

Print the group memberships of USER or for the current process

gunzip gunzip [-cft] [FILE]...

Decompress FILEs (or stdin)

        -c      Write to stdout
        -f      Force
        -t      Test file integrity

gzip gzip [-cfd] [FILE]...

Compress FILEs (or stdin)

        -d      Decompress
        -c      Write to stdout
        -f      Force

halt halt [-d DELAY] [-n] [-f] [-w]

Halt the system

        -d SEC  Delay interval
        -n      Do not sync
        -f      Force (dont go through init)
        -w      Only write a wtmp record

head head [OPTIONS] [FILE]...

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

        -n N[kbm]       Print first N lines
        -c N[kbm]       Print first N bytes
        -q              Never print headers
        -v              Always print headers

N may be suffixed by k (x1024), b (x512), or m (x1024^2).

hexdump hexdump [-bcCdefnosvx] [FILE]...

Display FILEs (or stdin) in a user specified format

        -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

hostid hostid

Print out a unique 32-bit identifier for the machine

hostname hostname [OPTIONS] [HOSTNAME | -F FILE]

Get 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 FILEs content as hostname

httpd 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

        -i              Inetd mode
        -f              Dont daemonize
        -v[v]           Verbose
        -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 .)
        -c FILE         Configuration file (default {/etc,HOME}/httpd.conf)
        -m STRING       MD5 crypt STRING
        -e STRING       HTML encode STRING
        -d STRING       URL decode STRING

hwclock hwclock [-r|--show] [-s|--hctosys] [-w|--systohc] [-t|--systz] [-l|--localtime] [-u|--utc] [-f|--rtc FILE]

Query and set hardware clock (RTC)

        -r      Show hardware clock time
        -s      Set system time from hardware clock
        -w      Set hardware clock from system time
        -t      Set in-kernel timezone, correct system time
                if hardware clock is in local time
        -u      Assume hardware clock is kept in UTC
        -l      Assume hardware clock is kept in local time
        -f FILE Use specified device (e.g. /dev/rtc2)

id id [OPTIONS] [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 ifconfig [-a] interface [address]

Configure a network interface

        [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] ...

init init

Init is the parent of all processes

insmod insmod FILE [SYMBOL=VALUE]...

Load the specified kernel modules into the kernel

ionice ionice [-c 1-3] [-n 0-7] [-p PID] [PROG]

Change I/O priority and class

        -c      Class. 1:realtime 2:best-effort 3:idle
        -n      Priority

ip 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] }


Calculate IP network settings from a IP address

        -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     Dont ever display error messages

kill kill [-l] [-SIG] PID...

Send a signal (default: TERM) to given PIDs

        -l      List all signal names and numbers

killall killall [-l] [-q] [-SIG] PROCESS_NAME...

Send a signal (default: TERM) to given processes

        -l      List all signal names and numbers
        -q      Dont complain if no processes were killed

klogd klogd [-c N] [-n]

Kernel logger

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

last last

Show listing of the last users that logged into the system

less less [-EMmNh~I?] [FILE]...

View FILE (or stdin) one screenful at a time

        -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 EOF


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

        -s      Make symlinks instead of hardlinks
        -f      Remove existing destinations
        -n      Dont 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 loadfont < font

Load a console font from stdin

loadkmap loadkmap < keymap

Load a binary keyboard translation table from stdin

logger logger [OPTIONS] [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 (numeric or facility.level pair)

login login [-p] [-h HOST] [[-f] USER]

Begin a new session on the system

        -f      Dont authenticate (user already authenticated)
        -h      Name of the remote host
        -p      Preserve environment

logname logname

Print the name of the current user

logread logread [-f]

Show messages in syslogd’s circular buffer

        -f      Output data as log grows

losetup losetup [-r] [-o OFS] LOOPDEV FILE - associate loop devices
        losetup -d LOOPDEV - disassociate
        losetup [-f] - show

        -o OFS  Start OFS bytes into FILE
        -r      Read-only
        -f      Show first free loop device

ls ls [-1AaCxdLHRFplinsehrSXvctu] [-w WIDTH] [FILE]...

List directory contents

        -1      One column output
        -a      Include entries which start with .
        -A      Like -a, but exclude . and ..
        -C      List by columns
        -x      List by lines
        -d      List directory entries instead of contents
        -L      Follow symlinks
        -H      Follow symlinks on command line
        -R      Recurse
        -p      Append / to dir entries
        -F      Append indicator (one of */=@|) to entries
        -l      Long listing format
        -i      List inode numbers
        -n      List numeric UIDs and GIDs instead of names
        -s      List allocated blocks
        -e      List full date and time
        -h      List sizes in human readable format (1K 243M 2G)
        -r      Sort in reverse order
        -S      Sort by size
        -X      Sort by extension
        -v      Sort by version
        -c      With -l: sort by ctime
        -t      With -l: sort by mtime
        -u      With -l: sort by atime
        -w N    Assume the terminal is N columns wide
        --color[={always,never,auto}]   Control coloring

lsmod lsmod

List the currently loaded kernel modules

lzcat lzcat FILE

Decompress to stdout

lzma lzma -d [-cf] [FILE]...

Decompress FILE (or stdin)

        -d      Decompress
        -c      Write to stdout
        -f      Force

md5sum md5sum [-c[sw]] [FILE]...

Print or check MD5 checksums

        -c      Check sums against list in FILEs
        -s      Dont output anything, status code shows success
        -w      Warn about improperly formatted checksum lines

mdev mdev [-s]

mdev -s is to be run during boot to scan /sys and populate /dev.

Bare mdev is a kernel hotplug helper. To activate it:
        echo /sbin/mdev >/proc/sys/kernel/hotplug

It uses /etc/mdev.conf with lines
        [-]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.

microcom microcom [-d DELAY] [-t TIMEOUT] [-s SPEED] [-X] TTY

Copy bytes for stdin to TTY and from TTY to stdout

        -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 mkdir [OPTIONS] DIRECTORY...


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

mkfifo mkfifo [-m MODE] NAME

Create named pipe

        -m MODE Mode (default a=rw)


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 and MINOR are ignored)

mkswap mkswap [-L LBL] BLOCKDEV [KBYTES]

Prepare BLOCKDEV to be used as swap partition

        -L LBL  Label

mktemp 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
        -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 modinfo [-adlp0] [-F keyword] 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
        -0              Separate output with NULs

modprobe 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 more [FILE]...

View FILE (or stdin) one screenful at a time

mount mount [OPTIONS] [-o OPTS] DEVICE NODE

Mount a filesystem. Filesystem autodetection requires /proc.

        -a              Mount all filesystems in fstab
        -i              Dont run mount helper
        -r              Read-only mount
        -w              Read-write mount (default)
        -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/rw           Same as -r/-w

There are filesystem-specific -o flags.

mt 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 mv [-fin] SOURCE DEST or: mv [-fin] SOURCE... DIRECTORY

Rename SOURCE to DEST, or move SOURCE(s) to DIRECTORY

        -f      Dont prompt before overwriting
        -i      Interactive, prompt before overwrite
        -n      Dont overwrite an existing file

nameif nameif [-s] [-c FILE] [IFNAME HWADDR]...

Rename network interface while it in the down state. The device with address HWADDR is renamed to IFACE.

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

nc nc [-iN] [-wN] [-l] [-p PORT] [-f FILE|IPADDR PORT] [-e PROG]

Open a pipe to IP:PORT or FILE

        -e PROG Run PROG after connect
        -l      Listen mode, for inbound connects
                (use -l twice with -e for persistent server)
        -p PORT Local port
        -w SEC  Timeout for connect
        -i SEC  Delay interval for lines sent
        -f FILE Use file (ala /dev/ttyS0) instead of network

netstat netstat [-ral] [-tuwx] [-en]

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      Dont resolve names

nslookup nslookup [HOST] [SERVER]

Query the nameserver for the IP address of the given HOST optionally using a specified DNS server

od 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 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


        -p,--strip N            Strip N leading components from file names
        -i,--input DIFF         Read DIFF instead of stdin
        -R,--reverse            Reverse patch
        -N,--forward            Ignore already applied patches
        -E,--remove-empty-files Remove output files if they become empty

pidof pidof [NAME]...

List PIDs of all processes with names that match NAMEs

ping ping [OPTIONS] HOST

Send ICMP ECHO_REQUEST packets to network hosts

        -4,-6           Force IP or IPv6 name resolution
        -c CNT          Send only CNT pings
        -s SIZE         Send SIZE data bytes in packets (default:56)
        -t TTL          Set TTL
        -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 ping6 [OPTIONS] HOST

Send ICMP ECHO_REQUEST packets to network hosts

        -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 pivot_root NEW_ROOT PUT_OLD

Move the current root file system to PUT_OLD and make NEW_ROOT the new root file system

poweroff poweroff [-d DELAY] [-n] [-f]

Halt and shut off power

        -d SEC  Delay interval
        -n      Do not sync
        -f      Force (dont go through init)

printf printf FORMAT [ARG]...

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

ps ps [-o COL1,COL2=HEADER] [-T]

Show list of processes

        -o COL1,COL2=HEADER     Select columns for display
        -T                      Show threads

pwd pwd

Print the full filename of the current working directory

rdate rdate [-sp] HOST

Get and possibly set the system date and time from a remote HOST

        -s      Set the system date and time (default)
        -p      Print the date and time

readlink readlink [-fnv] FILE

Display the value of a symlink

        -f      Canonicalize by following all symlinks
        -n      Dont add newline
        -v      Verbose

realpath realpath FILE...

Return the absolute pathnames of given FILE

reboot reboot [-d DELAY] [-n] [-f]

Reboot the system

        -d SEC  Delay interval
        -n      Do not sync
        -f      Force (dont go through init)

renice renice {{-n INCREMENT} | PRIORITY} [[-p | -g | -u] ID...]

Change scheduling priority for a running process

        -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

Reset the screen

rev rev [FILE]...

Reverse lines of FILE

rm rm [-irf] FILE...

Remove (unlink) FILEs

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

rmdir rmdir [OPTIONS] DIRECTORY...

Remove DIRECTORY if it is empty

        -p|--parents    Include parents

rmmod 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 route [{add|del|delete}]

Edit kernel routing tables

        -n      Dont resolve names
        -e      Display other/more information
        -A inet{6}      Select address family

rpm rpm -i PACKAGE.rpm; rpm -qp[ildc] PACKAGE.rpm

Manipulate RPM packages


        -i      Install package
        -qp     Query package
        -i      Show information
        -l      List contents
        -d      List documents
        -c      List config files

rpm2cpio rpm2cpio package.rpm

Output a cpio archive of the rpm file

run-parts run-parts [-t] [-a ARG] [-u MASK] DIRECTORY

Run a bunch of scripts in DIRECTORY

        -t      Print what would be run, but dont actually run anything
        -a ARG  Pass ARG as argument for every program
        -u MASK Set the umask to MASK before running every program

sed sed [-inr] [-f FILE]... [-e CMD]... [FILE]... or: sed [-inr] CMD [FILE]...

        -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 (else sends result to stdout)
        -n      Suppress automatic printing of pattern space
        -r      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).

seq 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

setkeycodes 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.

setsid setsid PROG ARGS

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.

sh sh [-/+OPTIONS] [-/+o OPT]... [-c ’SCRIPT’ [ARG0 [ARGS]] / FILE [ARGS]]

Unix shell interpreter

sha1sum sha1sum [-c[sw]] [FILE]...

Print or check SHA1 checksums

        -c      Check sums against list in FILEs
        -s      Dont output anything, status code shows success
        -w      Warn about improperly formatted checksum lines

sha256sum sha256sum [-c[sw]] [FILE]...

Print or check SHA256 checksums

        -c      Check sums against list in FILEs
        -s      Dont output anything, status code shows success
        -w      Warn about improperly formatted checksum lines

sha512sum sha512sum [-c[sw]] [FILE]...

Print or check SHA512 checksums

        -c      Check sums against list in FILEs
        -s      Dont output anything, status code shows success
        -w      Warn about improperly formatted checksum lines

sleep 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 sort [-nrugMcszbdfimSTokt] [-o FILE] [-k start[.offset][opts][,end[.offset][opts]] [-t CHAR] [FILE]...

Sort lines of text

        -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 (dont sort ties alphabetically)
        -u      Suppress duplicate lines
        -z      Lines are terminated by NUL, not newline
        -mST    Ignored for GNU compatibility

start-stop-daemon start-stop-daemon [OPTIONS] [-S|-K] ... [-- ARGS...]

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 users 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/{exe,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

        -o,--oknodo             Exit with status 0 if nothing is done
        -v,--verbose            Verbose
        -q,--quiet              Quiet

stat stat [OPTIONS] FILE...

Display file (default) or filesystem status

        -c fmt  Use the specified format
        -f      Display filesystem status
        -L      Follow 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     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 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 strings [-afo] [-n LEN] [FILE]...

Display printable strings in a binary file

        -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 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

swapoff swapoff [-a] [DEVICE]

Stop swapping on DEVICE

        -a      Stop swapping on all swap devices

swapon swapon [-a] [DEVICE]

Start swapping on DEVICE

        -a      Start swapping on all swap devices

switch_root 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.

        -c DEV  Reopen stdio to DEV after switch

sync sync

Write all buffered blocks to disk

sysctl sysctl [OPTIONS] [VALUE]...

Configure kernel parameters at runtime

        -n      Dont print key names
        -e      Dont 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 syslogd [OPTIONS]

System logging utility (this version of syslogd ignores /etc/syslog.conf)

        -n              Run in foreground
        -O FILE         Log to FILE (default:/var/log/messages)
        -l N            Log only messages more urgent than prio N (1-8)
        -S              Smaller output
        -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)
        -C[size_kb]     Log to shared mem buffer (use logread to read it)

tac tac [FILE]...

Concatenate FILEs and print them in reverse

tail tail [OPTIONS] [FILE]...

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

        -f              Print data as file grows
        -s SECONDS      Wait SECONDS between reads with -f
        -n N[kbm]       Print last N lines
        -c N[kbm]       Print last N bytes
        -q              Never print headers
        -v              Always print headers

N may be suffixed by k (x1024), b (x512), or m (x1024^2). If N starts with a ’+’, output begins with the Nth item from the start of each file, not from the end.

tar tar -[cxtZzjahmvO] [-f TARFILE] [-C DIR] [FILE]...

Create, extract, or list files from a tar file


        c       Create
        x       Extract
        t       List
        f       Name of TARFILE (- for stdin/out)
        C       Change to DIR before operation
        v       Verbose
        Z       (De)compress using compress
        z       (De)compress using gzip
        j       (De)compress using bzip2
        a       (De)compress using lzma
        O       Extract to stdout
        h       Follow symlinks
        m       Dont restore mtime

taskset taskset [-p] [MASK] [PID | PROG ARGS]

Set or get CPU affinity

        -p      Operate on an existing PID

tee tee [-ai] [FILE]...

Copy stdin to each FILE, and also to stdout

        -a      Append to the given FILEs, dont overwrite
        -i      Ignore interrupt signals (SIGINT)

telnet telnet [-a] [-l USER] HOST [PORT]

Connect to telnet server

        -a      Automatic login with $USER variable
        -l USER Automatic login as USER

test test EXPRESSION ]

Check file types, compare values etc. Return a 0/1 exit code depending on logical value of EXPRESSION

tftp tftp [OPTIONS] HOST [PORT]

Transfer a file from/to tftp server

        -l FILE Local FILE
        -r FILE Remote FILE
        -g      Get file
        -p      Put file
        -b SIZE Transfer blocks of SIZE octets

time time [-v] PROG ARGS

Run PROG, display resource usage when it exits

        -v      Verbose

timeout 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 top [-b] [-nCOUNT] [-dSECONDS]

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

        N/M/P/T: sort by pid/mem/cpu/time
        R: reverse sort
        H: toggle threads
        Q,^C: exit


        -b      Batch mode
        -n N    Exit after N iterations
        -d N    Delay between updates

touch touch [-c] [-d DATE] [-t DATE] [-r FILE] FILE...

Update the last-modified date on the given FILE[s]

        -c      Dont create files
        -d DT   Date/time to use
        -t DT   Date/time to use
        -r FILE Use FILEs date/time

tr 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 traceroute [-46FIldnrv] [-f 1ST_TTL] [-m MAXTTL] [-p PORT] [-q PROBES]
        [-s SRC_IP] [-t TOS] [-w WAIT_SEC] [-g GATEWAY] [-i IFACE]
        [-z PAUSE_MSEC] HOST [BYTES]

Trace the route to HOST

        -4,-6   Force IP or IPv6 name resolution
        -F      Set the dont 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 numeric addresses
        -r      Bypass routing tables, send directly to HOST
        -v      Verbose
        -m      Max time-to-live (max number of hops)
        -p      Base UDP port number used in probes
                (default 33434)
        -q      Number of probes per TTL (default 3)
        -s      IP address to use as the source address
        -t      Type-of-service in probe packets (default 0)
        -w      Time in seconds to wait for a response (default 3)
        -g      Loose source route gateway (8 max)

traceroute6 traceroute6 [-dnrv] [-m MAXTTL] [-p PORT] [-q PROBES]
        [-s SRC_IP] [-t TOS] [-w WAIT_SEC] [-i IFACE]
        HOST [BYTES]

Trace the route to HOST

        -d      Set SO_DEBUG options to socket
        -n      Print numeric addresses
        -r      Bypass routing tables, send directly to HOST
        -v      Verbose
        -m      Max time-to-live (max number of hops)
        -p      Base UDP port number used in probes
                (default is 33434)
        -q      Number of probes per TTL (default 3)
        -s      IP address to use as the source address
        -t      Type-of-service in probe packets (default 0)
        -w      Time in seconds to wait for a response (default 3)

true true

Return an exit code of TRUE (0)

tty tty

Print file name of stdin’s terminal

        -s      Print nothing, only return exit status

udhcpc udhcpc [-fbnqoCRB] [-i IFACE] [-r IP] [-s PROG] [-p PIDFILE]
        [-V VENDOR] [-x OPT:VAL]... [-O OPT]...

        -i,--interface IFACE    Interface to use (default eth0)
        -p,--pidfile FILE       Create pidfile
        -s,--script PROG        Run PROG at DHCP events (default /etc/udhcpc/default.script)
        -B,--broadcast          Request broadcast replies
        -t,--retries N          Send up to N discover packets
        -T,--timeout N          Pause between packets (default 3 seconds)
        -A,--tryagain N         Wait N seconds after failure (default 20)
        -f,--foreground         Run in foreground
        -b,--background         Background if lease is not obtained
        -n,--now                Exit if lease is not obtained
        -q,--quit               Exit after obtaining lease
        -R,--release            Release IP on exit
        -S,--syslog             Log to syslog too
        -a,--arping             Use arping to validate offered address
        -O,--request-option OPT Request option OPT from server (cumulative)
        -o,--no-default-options Dont request any options (unless -O is given)
        -r,--request IP         Request this IP address
        -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)
        -F,--fqdn NAME          Ask server to update DNS mapping for NAME
        -V,--vendorclass VENDOR Vendor identifier (default udhcp VERSION)
        -C,--clientid-none      Dont send MAC as client identifier

        USR1    Renew lease
        USR2    Release lease

udhcpd udhcpd [-fS] [CONFFILE]

DHCP server

        -f      Run in foreground
        -S      Log to syslog too


Unmount file systems

        -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      Dont free loop device even if it has been used

uname uname [-amnrspv]

Print system information

        -a      Print all
        -m      The machine (hardware) type
        -n      Hostname
        -r      OS release
        -s      OS name (default)
        -p      Processor type
        -v      OS version

uncompress uncompress [-cf] [FILE]...

Decompress .Z file[s]

        -c      Write to stdout
        -f      Overwrite

unexpand unexpand [-fa][-t N] [FILE]...

Convert spaces to tabs, writing to stdout

        -a,--all        Convert all blanks
        -f,--first-only Convert only leading blanks
        -t,--tabs=N     Tabstops every N chars

uniq uniq [-cdu][-f,s,w N] [INPUT [OUTPUT]]

Discard duplicate lines

        -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 unix2dos [-ud] [FILE]

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

        -u      dos2unix
        -d      unix2dos

unlzma unlzma [-cf] [FILE]...

Decompress FILE (or stdin)

        -c      Write to stdout
        -f      Force

unxz unxz [-cf] [FILE]...

Decompress FILE (or stdin)

        -c      Write to stdout
        -f      Force

unzip unzip [-opts[modifiers]] FILE[.zip] [LIST] [-x XLIST] [-d DIR]

Extract files from ZIP archives

        -l      List archive contents (with -q for short form)
        -n      Never overwrite files (default)
        -o      Overwrite
        -p      Send output to stdout
        -q      Quiet
        -x XLST Exclude these files
        -d DIR  Extract files into DIR

uptime uptime

Display the time since the last boot

usleep usleep N

Pause for N microseconds

uudecode uudecode [-o OUTFILE] [INFILE]

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

uuencode uuencode [-m] [FILE] STORED_FILENAME

Uuencode FILE (or stdin) to stdout

        -m      Use base64 encoding per RFC1521

vconfig vconfig COMMAND [OPTIONS]

Create and remove virtual ethernet devices

        add             IFACE VLAN_ID
        rem             VLAN_NAME
        set_flag        IFACE 0|1 VLAN_QOS
        set_egress_map  VLAN_NAME SKB_PRIO VLAN_QOS
        set_ingress_map VLAN_NAME SKB_PRIO VLAN_QOS
        set_name_type   NAME_TYPE

vi vi [OPTIONS] [FILE]...


        -c      Initial command to run ($EXINIT also available)
        -R      Read-only
        -H      Short help regarding available features

watch watch [-n SEC] [-t] PROG ARGS

Run PROG periodically

        -n      Loop period in seconds (default 2)
        -t      Dont print header

watchdog 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 wc [-cmlwL] [FILE]...

Count lines, words, and bytes for each FILE (or stdin)

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

wget wget [-c|--continue] [-s|--spider] [-q|--quiet] [-O|--output-document FILE]
        [--header ’header: value’] [-Y|--proxy on/off] [-P DIR]
        [--no-check-certificate] [-U|--user-agent AGENT] URL...

Retrieve files via HTTP or FTP

        -s      Spider mode - only check file existence
        -c      Continue retrieval of aborted transfer
        -q      Quiet
        -P DIR  Save to DIR (default .)
        -O FILE Save to FILE (- for stdout)
        -U STR  Use STR for User-Agent header
        -Y      Use proxy (on or off)

which which [COMMAND]...

Locate a COMMAND

who who [-a]

Show who is logged on

        -a      Show all
        -H      Print column headers

whoami whoami

Print the user name associated with the current effective user id

xargs xargs [OPTIONS] [PROG ARGS]

Run PROG on every item given by stdin

        -p      Ask user whether to run each command
        -r      Dont 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

xz xz -d [-cf] [FILE]...

Decompress FILE (or stdin)

        -d      Decompress
        -c      Write to stdout
        -f      Force

xzcat xzcat FILE

Decompress to stdout

yes yes [STRING]

Repeatedly output a line with STRING, or ’y’

zcat 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 <vda.linux@googlemail.com>


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 <emanuele.aina@tiscali.it>

Erik Andersen <andersen@codepoet.org>

    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 <l.d.anderson@warwick.ac.uk>

    rpm2cpio, unzip, get_header_cpio, read_gz interface, rpm

Jeff Angielski <jeff@theptrgroup.com>

    ftpput, ftpget

Edward Betts <edward@debian.org>

    expr, hostid, logname, whoami

John Beppu <beppu@codepoet.org>

    du, nslookup, sort

Brian Candler <B.Candler@pobox.com>


Randolph Chung <tausq@debian.org>

    fbset, ping, hostname

Dave Cinege <dcinege@psychosis.com>

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

Jordan Crouse <jordan@cosmicpenguin.net>


Magnus Damm <damm@opensource.se>

    tftp client insmod powerpc support

Larry Doolittle <ldoolitt@recycle.lbl.gov>

    pristine source directory compilation, lots of patches and fixes.

Glenn Engel <glenne@engel.org>


Gennady Feldman <gfeldman@gena01.com>

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

Karl M. Hegbloom <karlheg@debian.org>

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

Daniel Jacobowitz <dan@debian.org>


Matt Kraai <kraai@alumni.cmu.edu>

    documentation, bugfixes, test suite

Stephan Linz <linz@li-pro.net>

    ipcalc, Red Hat equivalence

John Lombardo <john@deltanet.com>


Glenn McGrath <bug1@iinet.net.au>

    Common unarchiving code and unarchiving applets, ifupdown, ftpgetput,
    nameif, sed, patch, fold, install, uudecode.
    Various bugfixes, review and apply numerous patches.

Manuel Novoa III <mjn3@codepoet.org>

    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 <dzo@simtreas.ru>

    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 <bruce@pixar.com>

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

Tim Riker <Tim@Rikers.org>

    bug fixes, member of fan club

Kent Robotti <robotti@metconnect.com>

    reset, tons and tons of bug reports and patches.

Chip Rosenthal <chip@unicom.com>, <crosenth@covad.com>

    wget - Contributed by permission of Covad Communications

Pavel Roskin <proski@gnu.org>

    Lots of bugs fixes and patches.

Gyepi Sam <gyepi@praxis-sw.com>

    Remote logging feature for syslogd

Linus Torvalds <torvalds@transmeta.com>

    mkswap, fsck.minix, mkfs.minix

Mark Whitley <markw@codepoet.org>

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

Charles P. Wright <cpwright@villagenet.com>

    gzip, mini-netcat(nc)

Enrique Zanardi <ezanardi@ull.es>

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

Tito Ragusa <farmatito@tiscali.it>

    devfsd and size optimizations in strings, openvt and deallocvt.

Paul Fox <pgf@foxharp.boston.ma.us>

    vi editing mode for ash, various other patches/fixes

Roberto A. Foglietta <me@roberto.foglietta.name>

    port: dnsd

Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>


Mike Frysinger <vapier@gentoo.org>

    initial e2fsprogs, printenv, setarch, sum, misc

Jie Zhang <jie.zhang@analog.com>

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

version 1.20.2 BUSYBOX (1) 2012-09-20
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