From Linux Man Pages
BusyBox - The Swiss Army Knife of Embedded Linux
SYNTAX
BusyBox <function> [arguments...] # or
<function> [arguments...] # if symlinked
DESCRIPTION
BusyBox combines tiny versions of many common UNIX utilities into a single small executable. It provides minimal-
ist 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 PREFIX. 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 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 PREFIX.
USAGE
BusyBox is a multi-call binary. A multi-call binary is an executable program that performs the same job as more
than one utility program. That means there is just a single BusyBox binary, but that single binary acts like a
large number of utilities. This allows BusyBox to be smaller since all the built-in utility programs (we call
them applets) can share code for many common operations.
You can also invoke BusyBox by issuing a command as an argument on the command line. For example, entering
/bin/busybox ls
will also cause BusyBox to behave as 'ls'.
Of course, adding '/bin/busybox' into every command would be painful. So most people will invoke BusyBox using
links to the BusyBox binary.
For example, entering
ln -s /bin/busybox ls
./ls
will cause BusyBox to behave as 'ls' (if the 'ls' command has been compiled into BusyBox). 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.
COMMON OPTIONS
Most BusyBox commands 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.
COMMANDS
Currently defined functions include:
[, [[, addgroup, adduser, adjtimex, ar, arping, ash, awk,
basename, bbconfig, bunzip2, busybox, bzcat, cal, cat, catv,
chattr, chgrp, chmod, chown, chroot, chvt, cksum, clear, cmp,
comm, cp, cpio, crond, crontab, cut, date, dc, dd, deallocvt,
delgroup, deluser, devfsd, df, diff, dirname, dmesg, dnsd,
dos2unix, dpkg, dpkg_deb, du, dumpkmap, dumpleases, e2fsck, echo,
ed, eject, env, ether_wake, expr, fakeidentd, false, fbset,
fdflush, fdformat, fdisk, find, fold, free, freeramdisk, fsck,
fsck_minix, ftpget, ftpput, fuser, getopt, getty, grep, gunzip,
gzip, halt, hdparm, head, hexdump, hostid, hostname, httpd,
hwclock, id, ifconfig, ifdown, ifup, inetd, init, insmod,
install, ip, ipaddr, ipcalc, ipcrm, ipcs, iplink, iproute,
iptunnel, kill, killall, klogd, lash, last, length, less, ln,
loadfont, loadkmap, logger, login, logname, logread, losetup, ls,
lsattr, lsmod, lzmacat, makedevs, md5sum, mdev, mesg, mkdir,
mke2fs, mkfifo, mkfs_minix, mknod, mkswap, mktemp, modprobe,
more, mount, mountpoint, mt, mv, nameif, nc, netstat, nice,
nohup, nslookup, od, openvt, passwd, patch, pidof, ping, ping6,
pivot_root, poweroff, printenv, printf, ps, pwd, rdate, readlink,
readprofile, realpath, reboot, renice, reset, rm, rmdir, rmmod,
route, rpm, rpm2cpio, run_parts, runlevel, rx, sed, seq, setarch,
setconsole, setkeycodes, setlogcons, setsid, sha1sum, sleep,
sort, start_stop_daemon, stat, strings, stty, su, sulogin, sum,
swapoff, swapon, switch_root, sync, sysctl, syslogd, tail, tar,
tee, telnet, telnetd, test, tftp, time, top, touch, tr,
traceroute, true, tty, tune2fs, udhcpc, udhcpd, umount, uname,
uncompress, uniq, unix2dos, unlzma, unzip, uptime, usleep,
uudecode, uuencode, vconfig, vi, vlock, watch, watchdog, wc,
wget, which, who, whoami, xargs, yes, zcat, zcip
COMMAND DESCRIPTIONS
addgroup
addgroup [-g GID] group_name [user_name]
Adds a group to the system
Options:
-g GID specify gid
adduser
adduser [OPTIONS] user_name
Adds a user to the system
Options:
-h DIR Assign home directory DIR
-g GECOS Assign gecos field GECOS
-s SHELL Assign login shell SHELL
-G Add the user to existing group GROUP
-S create a system user (ignored)
-D Do not assign a password (logins still possible via ssh)
-H Do not create the home directory
adjtimex
adjtimex [-q] [-o offset] [-f frequency] [-p timeconstant] [-t tick]
Reads and optionally sets system timebase parameters. See adjtimex(2).
Options:
-q quiet mode - do not print
-o offset time offset, microseconds
-f frequency frequency adjust, integer kernel units (65536 is 1ppm)
(positive values make the system clock run fast)
-t tick microseconds per tick, usually 10000
-p timeconstant
ar ar [-o] [-v] [-p] [-t] [-x] ARCHIVE FILES
Extract or list FILES from an ar archive.
Options:
-o preserve original dates
-p extract to stdout
-t list
-x extract
-v verbosely list files processed
arping
arping [-fqbDUA] [-c count] [-w timeout] [-i device] [-s sender] target
Ping hosts by ARP requests/replies.
Options:
-f Quit on first ARP reply
-q Be quiet
-b Keep broadcasting, don't go unicast
-D Duplicated address detection mode
-U Unsolicited ARP mode, update your neighbours
-A ARP answer mode, update your neighbours
-c count Stop after sending count ARP request packets
-w timeout Time to wait for ARP reply, in seconds
-i device Outgoing interface name, default is eth0
-s sender Set specific sender IP address
target Target IP address of ARP request
ash ash [FILE]... or: ash -c command [args]...
The ash shell (command interpreter)
awk awk [OPTION]... [program-text] [FILE ...]
Options:
-v var=val assign value 'val' to variable 'var'
-F sep use 'sep' as field separator
-f progname read program source from file 'progname'
basename
basename FILE [SUFFIX]
Strips directory path and suffixes from FILE. If specified, also removes any trailing SUFFIX.
Example:
$ basename /usr/local/bin/foo
foo
$ basename /usr/local/bin/
bin
$ basename /foo/bar.txt .txt
bar
bbconfig
bbconfig
Print the config file which built busybox
bunzip2
bunzip2 [OPTION]... [FILE]
Uncompress FILE (or standard input if FILE is '-' or omitted).
Options:
-c Write output to standard output
-f Force
busybox
busybox
Hello world!
bzcat
bzcat FILE
Uncompress to stdout.
cal cal [-jy] [[month] year]
Display a calendar.
Options:
-j Use julian dates
-y Display the entire year
cat cat [-u] [FILE]...
Concatenates FILE(s) and prints them to stdout.
Options:
-u ignored since unbuffered i/o is always used
Example:
$ cat /proc/uptime
110716.72 17.67
catv
catv [-etv] [FILE]...
Display nonprinting characters as ^x or M-x.
-e End each line with $
-t Show tabs as ^I
-v Don't use ^x or M-x escapes.
chattr
chattr [-R] [-+=AacDdijsStTu] [-v version] files...
change file attributes on an ext2 fs
Modifiers:
- remove attributes
+ add attributes
= set attributes
Attributes:
A don't track atime
a append mode only
c enable compress
D write dir contents synchronously
d do not backup with dump
i cannot be modified (immutable)
j write all data to journal first
s zero disk storage when deleted
S write file contents synchronously
t disable tail-merging of partial blocks with other files
u allow file to be undeleted
Options:
-R recursively list subdirectories
-v set the file's version/generation number
chgrp
chgrp [OPTION]... GROUP FILE...
Change the group membership of each FILE to GROUP.
Options:
-R Changes files and directories recursively
Example:
$ ls -l /tmp/foo
-r--r--r-- 1 andersen andersen 0 Apr 12 18:25 /tmp/foo
$ chgrp root /tmp/foo
$ ls -l /tmp/foo
-r--r--r-- 1 andersen root 0 Apr 12 18:25 /tmp/foo
chmod
chmod [-R] MODE[,MODE]... FILE...
Each MODE is one or more of the letters ugoa, one of the symbols +-= and one or more of the letters rwxst.
Options:
-R Changes files and directories recursively
Example:
$ ls -l /tmp/foo
-rw-rw-r-- 1 root root 0 Apr 12 18:25 /tmp/foo
$ chmod u+x /tmp/foo
$ ls -l /tmp/foo
-rwxrw-r-- 1 root root 0 Apr 12 18:25 /tmp/foo*
$ chmod 444 /tmp/foo
$ ls -l /tmp/foo
-r--r--r-- 1 root root 0 Apr 12 18:25 /tmp/foo
chown
chown [ -Rh ]... OWNER[<.|:>[GROUP]] FILE...
Change the owner and/or group of each FILE to OWNER and/or GROUP.
Options:
-R Changes files and directories recursively
-h Do not dereference symbolic links
Example:
$ ls -l /tmp/foo
-r--r--r-- 1 andersen andersen 0 Apr 12 18:25 /tmp/foo
$ chown root /tmp/foo
$ ls -l /tmp/foo
-r--r--r-- 1 root andersen 0 Apr 12 18:25 /tmp/foo
$ chown root.root /tmp/foo
ls -l /tmp/foo
-r--r--r-- 1 root root 0 Apr 12 18:25 /tmp/foo
chroot
chroot NEWROOT [COMMAND...]
Run COMMAND with root directory set to NEWROOT.
Example:
$ ls -l /bin/ls
lrwxrwxrwx 1 root root 12 Apr 13 00:46 /bin/ls -> /BusyBox
# mount /dev/hdc1 /mnt -t minix
# chroot /mnt
# ls -l /bin/ls
-rwxr-xr-x 1 root root 40816 Feb 5 07:45 /bin/ls*
chvt
chvt N
Changes the foreground virtual terminal to /dev/ttyN
cksum
cksum FILES...
Calculates the CRC32 checksums of FILES.
clear
clear
Clear screen.
cmp cmp [-l] [-s] FILE1 [FILE2]
Compares FILE1 vs stdin if FILE2 is not specified.
Options:
-l Write the byte numbers (decimal) and values (octal)
for all differing bytes
-s quiet mode - do not print
comm
comm [-123] FILE1 FILE2
Compares FILE1 to FILE2, or to stdin if = is specified.
Options:
-1 Suppress lines unique to FILE1
-2 Suppress lines unique to FILE2
-3 Suppress lines common to both files
cp cp [OPTION]... SOURCE DEST
Copies SOURCE to DEST, or multiple SOURCE(s) to DIRECTORY.
-a Same as -dpR
-d,-P Preserves links
-H,-L Dereference all symlinks (implied by default)
-p Preserves file attributes if possible
-f force (implied; ignored) - always set
-i interactive, prompt before overwrite
-R,-r Copies directories recursively
cpio
cpio -[dimtuv][F cpiofile]
Extract or list files from a cpio archive Main operation mode:
d make leading directories
i extract
m preserve mtime
t list
v verbose
u unconditional overwrite
F input from file
crond
crond -d[#] -c <crondir> -f -b
-d [#] -l [#] -S -L logfile -f -b -c dir
-d num debug level
-l num log level (8 - default)
-S log to syslogd (default)
-L file log to file
-f run in foreground
-b run in background (default)
-c dir working dir
crontab
crontab [-c dir] {file|-}|[-u|-l|-e|-d user]
file <opts> replace crontab from file
- <opts> replace crontab from stdin
-u user specify user
-l [user] list crontab for user
-e [user] edit crontab for user
-d [user] delete crontab for user
-c dir specify crontab directory
cut cut [OPTION]... [FILE]...
Prints selected fields from each input FILE to standard output.
Options:
-b LIST Output only bytes from LIST
-c LIST Output only characters from LIST
-d CHAR Use CHAR instead of tab as the field delimiter
-s Output only the lines containing delimiter
-f N Print only these fields
-n Ignored
Example:
$ echo "Hello world" | cut -f 1 -d ' '
Hello
$ echo "Hello world" | cut -f 2 -d ' '
world
date
date [OPTION]... [MMDDhhmm[[CC]YY][.ss]] [+FORMAT]
Displays the current time in the given FORMAT, or sets the system date.
Options:
-R Outputs RFC-822 compliant date string
-d STRING Displays time described by STRING, not `now'
USE_FEATURE_DATE_ISOFMT( B<-I>[TIMESPEC] Outputs an ISO-8601 compliant date/time string
TIMESPEC=`date' (or missing) for date only,
`hours', `minutes', or `seconds' for date and,
time to the indicated precision
-D hint Use 'hint' as date format, via strptime()
) B<-s> Sets time described by STRING
-r FILE Displays the last modification time of FILE
-u Prints or sets Coordinated Universal Time
Example:
$ date
Wed Apr 12 18:52:41 MDT 2000
dc dc expression ...
This is a Tiny RPN calculator that understands the following operations: +, add, -, sub, *, mul, /, div, %,
mod, **, exp, and, or, not, eor. For example: 'dc 2 2 add' -> 4, and 'dc 8 8 \* 2 2 + /' -> 16.
Options: p - Prints the value on the top of the stack, without altering the stack f - Prints the entire con-
tents of the stack without altering anything o - Pops the value off the top of the stack and uses it to set
the output radix
Only 10 and 16 are supported
Example:
$ dc 2 2 + p
4
$ dc 8 8 \* 2 2 + / p
16
$ dc 0 1 and p
0
$ dc 0 1 or p
1
$ echo 72 9 div 8 mul p | dc
64
dd dd [if=FILE] [of=FILE] " USE_FEATURE_DD_IBS_OBS("[ibs=N] [obs=N] ") "[bs=N] [count=N] [skip=N]
[seek=N]" USE_FEATURE_DD_IBS_OBS(" [conv=notrunc|noerror|sync]")
Copy a file, converting and formatting according to options
if=FILE read from FILE instead of stdin
of=FILE write to FILE instead of stdout
bs=N read and write N bytes at a time
USE_FEATURE_DD_IBS_OBS(" ibs=N read N bytes at a time
") USE_FEATURE_DD_IBS_OBS(" 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
USE_FEATURE_DD_IBS_OBS( conv=notrunc don't truncate output file
conv=noerror continue after read errors
conv=sync pad blocks with zeros
)
Numbers may be suffixed by c (x1), w (x2), b (x512), kD (x1000), k (x1024),
MD (x1000000), M (x1048576), GD (x1000000000) or G (x1073741824)
Example:
$ dd if=/dev/zero of=/dev/ram1 bs=1M count=4
4+0 records in
4+0 records out
deallocvt
deallocvt [N]
Deallocate unused virtual terminal /dev/ttyN
delgroup
delgroup GROUP
Deletes group GROUP from the system
deluser
deluser USER
Deletes user USER from the system
devfsd
devfsd mntpnt [-v] USE_DEVFSD_FG_NP("[-fg][-np]" )
Optional daemon for managing devfs permissions and old device name symlinks.
Options:
mntpnt The mount point where devfs is mounted.
-v Print the protocol version numbers for devfsd
and the kernel-side protocol version and exits. USE_DEVFSD_FG_NP( "
-fg Run the daemon in the foreground.
-np Exit after parsing the configuration file
and processing synthetic REGISTER events.
Do not poll for events.")
df df [-" USE_FEATURE_HUMAN_READABLE("hm") "k] [FILESYSTEM ...]
Print the filesystem space used and space available.
Options:
USE_FEATURE_HUMAN_READABLE(
-h print sizes in human readable format (e.g., 1K 243M 2G )
-m print sizes in megabytes
-k print sizes in kilobytes(default) ) SKIP_FEATURE_HUMAN_READABLE("
-k ignored")
Example:
$ df
Filesystem 1k-blocks Used Available Use% Mounted on
/dev/sda3 8690864 8553540 137324 98% /
/dev/sda1 64216 36364 27852 57% /boot
$ df /dev/sda3
Filesystem 1k-blocks Used Available Use% Mounted on
/dev/sda3 8690864 8553540 137324 98% /
diff
diff [-abdiNqrTstw] [-L LABEL] [-S FILE] [-U LINES] FILE1 FILE2
Compare files line by line and output the differences between them. This diff implementation only supports
unified diffs.
Options:
-a Treat all files as text
-b Ignore changes in the amount of whitespace
-d Try hard to find a smaller set of changes
-i Ignore case differences
-L Use LABEL instead of the filename in the unified header
-N Treat absent files as empty
-q Output only whether files differ
-r Recursively compare any subdirectories
-S Start with FILE when comparing directories
-T Make tabs line up by prefixing a tab when necessary
-s Report when two files are the same
-t Expand tabs to spaces in output
-U Output LINES lines of context
-w Ignore all whitespace
dirname
dirname FILENAME
Strips non-directory suffix from FILENAME
Example:
$ dirname /tmp/foo
/tmp
$ dirname /tmp/foo/
/tmp
dmesg
dmesg [-c] [-n LEVEL] [-s SIZE]
Prints or controls the kernel ring buffer
Options:
-c Clears the ring buffer's contents after printing
-n LEVEL Sets console logging level
-s SIZE Use a buffer of size SIZE
dnsd
dnsd [-c config] [-t seconds] [-p port] [-i iface-ip] [-d]
Small and static DNS server daemon
Options:
-c config filename
-t TTL in seconds
-p listening port
-i listening iface ip (default all)
-d daemonize
dos2unix
dos2unix [option] [FILE]
Converts FILE from dos format to unix format. When no option is given, the input is converted to the oppo-
site output format. When no file is given, uses stdin for input and stdout for output.
Options:
-u output will be in UNIX format
-d output will be in DOS format
dpkg
dpkg [-ilCPru] [-F option] package_name
dpkg is a utility to install, remove and manage Debian packages.
Options:
-i Install the package
-l List of installed packages
-C Configure an unpackaged package
-F depends Ignore dependency problems
-P Purge all files of a package
-r Remove all but the configuration files for a package
-u Unpack a package, but don't configure it
dpkg-deb
dpkg-deb [-cefxX] FILE [argument]
Perform actions on Debian packages (.debs)
Options:
-c List contents of filesystem tree
-e Extract control files to [argument] directory
-f Display control field name starting with [argument]
-x Extract packages filesystem tree to directory
-X Verbose extract
Example:
$ dpkg-deb -X ./busybox_0.48-1_i386.deb /tmp
du du [-aHLdclsx" USE_FEATURE_HUMAN_READABLE("hm") "k] [FILE]...
Summarizes disk space used for each FILE and/or directory. Disk space is printed in units of USE_FEA-
TURE_DU_DEFAULT_BLOCKSIZE_1K("1024") SKIP_FEATURE_DU_DEFAULT_BLOCKSIZE_1K("512") bytes.
Options:
-a show sizes of files in addition to directories
-H follow symbolic links that are FILE command line args
-L follow all symbolic links encountered
-d N limit output to directories (and files with -a) of depth < N
-c output a grand total
-l count sizes many times if hard linked
-s display only a total for each argument
-x skip directories on different filesystems
USE_FEATURE_HUMAN_READABLE( -h print sizes in human readable format (e.g., 1K 243M 2G )
-m print sizes in megabytes
) -k print sizes in kilobytes USE_FEATURE_DU_DEFAULT_BLOCKSIZE_1K("(default)")
Example:
$ du
16 ./CVS
12 ./kernel-patches/CVS
80 ./kernel-patches
12 ./tests/CVS
36 ./tests
12 ./scripts/CVS
16 ./scripts
12 ./docs/CVS
104 ./docs
2417 .
dumpkmap
dumpkmap > keymap
Prints out a binary keyboard translation table to standard output.
Example:
$ dumpkmap > keymap
dumpleases
dumpleases [-r|-a] [-f LEASEFILE]
Displays the DHCP leases granted by udhcpd.
Options:
-f, --file=FILENAME Leases file to load
-r, --remaining Interpret lease times as time remaining
-a, --absolute Interpret lease times as expire time
e2fsck
e2fsck [-panyrcdfvstDFSV] [-b superblock] [-B blocksize] [-I inode_buffer_blocks] [-P process_inode_size]
[-l|-L bad_blocks_file] [-C fd] [-j external_journal] [-E extended-options] device
Check a Linux ext2/ext3 file system.
Options:
-p Automatic repair (no questions)
-n Make no changes to the filesystem
-y Assume 'yes' to all questions
-c Check for bad blocks and add them to the badblock list
-f Force checking even if filesystem is marked clean
-v Be verbose
-b superblock Use alternative superblock
-B blocksize Force blocksize when looking for superblock
-j journal Set location of the external journal
-l file Add to badblocks list
-L file Set badblocks list
echo
echo USE_FEATURE_FANCY_ECHO("[-neE] ") "[ARG ...]
Prints the specified ARGs to stdout
USE_FEATURE_FANCY_ECHO( Options:
-n suppress trailing newline
-e interpret backslash-escaped characters (i.e., \t=tab)
-E disable interpretation of backslash-escaped characters )
Example:
$ echo "Erik is cool"
Erik is cool
USE_FEATURE_FANCY_ECHO("$ echo -e "Erik\nis\ncool"
Erik
is
cool
$ echo "Erik\nis\ncool"
Erik\nis\ncool
")
ed ed #define ed_full_usage
eject
eject [-t] [DEVICE]
Eject specified DEVICE (or default /dev/cdrom).
Options:
-t close tray
env env [-iu] [-] [name=value]... [command]
Prints the current environment or runs a program after setting up the specified environment.
Options:
-, -i start with an empty environment
-u remove variable from the environment
ether_wake
ether_wake [-b] [-i iface] [-p aa:bb:cc:dd[:ee:ff]] 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.
Options:
-b Send wake-up packet to the broadcast address
-i iface Use interface ifname instead of the default "eth0"
-p pass Append the four or six byte password PW to the packet
expr
expr EXPRESSION
Prints the value of EXPRESSION to standard output.
EXPRESSION may be:
ARG1 | ARG2 ARG1 if it is neither null nor 0, otherwise ARG2
ARG1 & ARG2 ARG1 if neither argument is null or 0, otherwise 0
ARG1 < ARG2 ARG1 is less than ARG2
ARG1 <= ARG2 ARG1 is less than or equal to ARG2
ARG1 = ARG2 ARG1 is equal to ARG2
ARG1 != ARG2 ARG1 is unequal to ARG2
ARG1 >= ARG2 ARG1 is greater than or equal to ARG2
ARG1 > ARG2 ARG1 is greater than ARG2
ARG1 + ARG2 arithmetic sum of ARG1 and ARG2
ARG1 - ARG2 arithmetic difference of ARG1 and ARG2
ARG1 * ARG2 arithmetic product of ARG1 and ARG2
ARG1 / ARG2 arithmetic quotient of ARG1 divided by ARG2
ARG1 % ARG2 arithmetic remainder of ARG1 divided by ARG2
STRING : REGEXP anchored pattern match of REGEXP in STRING
match STRING REGEXP same as STRING : REGEXP
substr STRING POS LENGTH substring of STRING, POS counted from 1
index STRING CHARS index in STRING where any CHARS is found,
or 0
length STRING length of STRING
quote TOKEN interpret TOKEN as a string, even if
it is a keyword like `match' or an
operator like `/'
( EXPRESSION ) value of EXPRESSION
Beware that many operators need to be escaped or quoted for shells. Comparisons are arithmetic if both ARGs
are numbers, else lexicographical. Pattern matches return the string matched between \( and \) or null; if
\( and \) are not used, they return the number of characters matched or 0.
fakeidentd
fakeidentd [-b ip] [STRING]
Returns a set string to auth requests
-b Bind to ip address
STRING The ident answer string (default is nobody)
false
false
Return an exit code of FALSE(1).
Example:
$ false
$ echo $?
1
fbset
fbset [options] [mode]
Show and modify frame buffer settings
Example:
$ fbset
mode "1024x768-76"
# D: 78.653 MHz, H: 59.949 kHz, V: 75.694 Hz
geometry 1024 768 1024 768 16
timings 12714 128 32 16 4 128 4
accel false
rgba 5/11,6/5,5/0,0/0
endmode
fdflush
fdflush DEVICE
Forces floppy disk drive to detect disk change
fdformat
fdformat [-n] DEVICE
Low-level formats a floppy disk
Options:
-n Don't verify after format
fdisk
fdisk [-luv] [-C CYLINDERS] [-H HEADS] [-S SECTORS] [-b SSZ] DISK
Change partition table Options:
-l List partition table(s)
-u Give Start and End in sector (instead of cylinder) units
-s PARTITION Give partition size(s) in blocks
-b 2048: (for certain MO disks) use 2048-byte sectors
-C CYLINDERS Set the number of cylinders
-H HEADS Set the number of heads
-S SECTORS Set the number of sectors
-v Give fdisk version
find
find [PATH...] [EXPRESSION]
Search for files in a directory hierarchy. The default PATH is the current directory; default EXPRESSION is
'-print'
EXPRESSION may consist of:
-follow Dereference symbolic links
-name PATTERN File name (leading directories removed) matches PATTERN
-print Print (default and assumed)
USE_FEATURE_FIND_PRINT0( -print0 Delimit output with null characters rather than
newlines) USE_FEATURE_FIND_TYPE(
-type X Filetype matches X (where X is one of: f,d,l,b,c,...)) USE_FEATURE_FIND_PERM(
-perm PERMS Permissions match any of (+NNN); all of (-NNN);
or exactly (NNN)) USE_FEATURE_FIND_MTIME(
-mtime DAYS Modified time is greater than (+N); less than (-N);
or exactly (N) days) USE_FEATURE_FIND_MMIN(
-mmin MINS Modified time is greater than (+N); less than (-N);
or exactly (N) minutes) USE_FEATURE_FIND_NEWER(
-newer FILE Modified time is more recent than FILE's) USE_FEATURE_FIND_INUM(
-inum N File has inode number N) USE_FEATURE_FIND_EXEC(
-exec CMD Execute CMD with all instances of {} replaced by the
files matching EXPRESSION")
Example:
$ find / -name passwd
/etc/passwd
fold
fold [-bs] [-w WIDTH] [FILE]
Wrap input lines in each FILE (standard input by default), writing to standard output.
Options:
-b count bytes rather than columns
-s break at spaces
-w use WIDTH columns instead of 80
free
free
Displays the amount of free and used system memory
Example:
$ free
total used free shared buffers
Mem: 257628 248724 8904 59644 93124
Swap: 128516 8404 120112
Total: 386144 257128 129016
freeramdisk
freeramdisk DEVICE
Frees all memory used by the specified ramdisk.
Example:
$ freeramdisk /dev/ram2
fsck
fsck [-ANPRTV] [ -C [ fd ] ] [-t fstype] [fs-options] [filesys ...]
Check and repair filesystems.
Options:
-A Walk /etc/fstab and check all filesystems
-N Don't execute, just show what would be done
-P When using -A, check filesystems in parallel
-R When using -A, skip the root filesystem
-T Don't show title on startup
-V Verbose mode
-C Write status information to specified filedescriptor
-t List of filesystem types to check
fsck.minix
fsck.minix [-larvsmf] /dev/name
Performs a consistency check for MINIX filesystems.
Options:
-l Lists all filenames
-r Perform interactive repairs
-a Perform automatic repairs
-v verbose
-s Outputs super-block information
-m Activates MINIX-like "mode not cleared" warnings
-f Force file system check
ftpget
ftpget [options] remote-host local-file remote-file
Retrieve a remote file via FTP.
Options:
-c, --continue Continue a previous transfer
-v, --verbose Verbose
-u, --username Username to be used
-p, --password Password to be used
-P, --port Port number to be used
ftpput
ftpput [options] remote-host remote-file local-file
Store a local file on a remote machine via FTP.
Options:
-v, --verbose Verbose
-u, --username Username to be used
-p, --password Password to be used
-P, --port Port number to be used
fuser
fuser [options] file OR port/proto
Options:
-m Show all processes on the same mounted fs
-k Kill all processes that match.
-s Don't print or kill anything.
-4 When using port/proto only search IPv4 space
-6 When using port/proto only search IPv6 space
-SIGNAL When used with -k, this signal will be used to kill
getopt
getopt [OPTIONS]...
Parse command options
-a, --alternative Allow long options starting with single -
-l, --longoptions=longopts Long options to be recognized
-n, --name=progname The name under which errors are reported
-o, --options=optstring Short options to be recognized
-q, --quiet Disable error reporting by getopt(3)
-Q, --quiet-output No normal output
-s, --shell=shell Set shell quoting conventions
-T, --test Test for getopt(1) version
-u, --unquoted Do not quote the output
Example:
$ cat getopt.test
#!/bin/sh
GETOPT=`getopt -o ab:c:: --long a-long,b-long:,c-long:: \
-n 'example.busybox' -- "$@"`
if [ $? != 0 ] ; then exit 1 ; fi
eval set -- "$GETOPT"
while true ; do
case $1 in
-a|--a-long) echo "Option a" ; shift ;;
-b|--b-long) echo "Option b, argument `$2'" ; shift 2 ;;
-c|--c-long)
case "$2" in
"") echo "Option c, no argument"; shift 2 ;;
*) echo "Option c, argument `$2'" ; shift 2 ;;
esac ;;
--) shift ; break ;;
*) echo "Internal error!" ; exit 1 ;;
esac
done
getty
getty [OPTIONS]... baud_rate,... line [termtype]
Opens a tty, prompts for a login name, then invokes /bin/login
Options:
-h Enable hardware (RTS/CTS) flow control
-i Do not display /etc/issue before running login
-L Local line, so do not do carrier detect
-m Get baud rate from modem's CONNECT status message
-w Wait for a CR or LF before sending /etc/issue
-n Do not prompt the user for a login name
-f issue_file Display issue_file instead of /etc/issue
-l login_app Invoke login_app instead of /bin/login
-t timeout Terminate after timeout if no username is read
-I initstring Sets the init string to send before anything else
-H login_host Log login_host into the utmp file as the hostname
grep
grep [-ihHnqvs USE_FEATURE_GREP_EGREP_ALIAS("E") USE_FEATURE_GREP_CONTEXT("ABC") ] PATTERN
[FILEs...]
Search for PATTERN in each FILE or standard input.
Options:
-H prefix output lines with filename where match was found
-h suppress the prefixing filename on output
-i ignore case distinctions
-l list names of files that match
-L list names of files that do not match
-n print line number with output lines
-q be quiet. Returns 0 if PATTERN was found, 1 otherwise
-v select non-matching lines
-s suppress file open/read error messages
-c only print count of matching lines
-f read PATTERN from file
-e PATTERN is a regular expression
-F PATTERN is a set of newline-separated strings USE_FEATURE_GREP_EGREP_ALIAS("
-E PATTERN is an extended regular expression") USE_FEATURE_GREP_CONTEXT("
-A print NUM lines of trailing context") USE_FEATURE_GREP_CONTEXT("
-B print NUM lines of leading context") USE_FEATURE_GREP_CONTEXT("
-C print NUM lines of output context")
Example:
$ grep root /etc/passwd
root:x:0:0:root:/root:/bin/bash
$ grep ^[rR]oo. /etc/passwd
root:x:0:0:root:/root:/bin/bash
gunzip
gunzip [OPTION]... FILE
Uncompress FILE (or standard input if FILE is '-').
Options:
-c Write output to standard output
-f Force read when source is a terminal
-t Test compressed file integrity
Example:
$ ls -la /tmp/BusyBox*
-rw-rw-r-- 1 andersen andersen 557009 Apr 11 10:55 /tmp/BusyBox-0.43.tar.gz
$ gunzip /tmp/BusyBox-0.43.tar.gz
$ ls -la /tmp/BusyBox*
-rw-rw-r-- 1 andersen andersen 1761280 Apr 14 17:47 /tmp/BusyBox-0.43.tar
gzip
gzip [OPTION]... [FILE]...
Compress FILE(s) with maximum compression. When FILE is '-' or unspecified, reads standard input. Implies
-c.
Options:
-c Write output to standard output instead of FILE.gz
-d Decompress
-f Force write when destination is a terminal
Example:
$ ls -la /tmp/busybox*
-rw-rw-r-- 1 andersen andersen 1761280 Apr 14 17:47 /tmp/busybox.tar
$ gzip /tmp/busybox.tar
$ ls -la /tmp/busybox*
-rw-rw-r-- 1 andersen andersen 554058 Apr 14 17:49 /tmp/busybox.tar.gz
halt
halt [-d<delay>] [-n<nosync>] [-f<force>]
Halt the system. Options:
-d delay interval for halting
-n no call to sync()
-f force halt (don't go through init)
hdparm
hdparm [options] [device] ..
USE_FEATURE_HDPARM_GET_IDENTITY(" If no device name is specified try to read from stdin.
")
Options:
-a get/set fs readahead
-A set drive read-lookahead flag (0/1)
-b get/set bus state (0 == off, 1 == on, 2 == tristate)
-B set Advanced Power Management setting (1-255)
-c get/set IDE 32-bit IO setting
-C check IDE power mode status
USE_FEATURE_HDPARM_HDIO_GETSET_DMA(" -d get/set using_dma flag
") B<-D> enable/disable drive defect-mgmt
-f flush buffer cache for device on exit
-g display drive geometry
-h display terse usage information
USE_FEATURE_HDPARM_GET_IDENTITY(" -i display drive identification
") USE_FEATURE_HDPARM_GET_IDENTITY(" B<-I> detailed/current information directly from drive
") B<-k> get/set keep_settings_over_reset flag (0/1)
-K set drive keep_features_over_reset flag (0/1)
-L set drive doorlock (0/1) (removable harddisks only)
-m get/set multiple sector count
-n get/set ignore-write-errors flag (0/1)
-p set PIO mode on IDE interface chipset (0,1,2,3,4,...)
-P set drive prefetch count
-q change next setting quietly
-Q get/set DMA tagged-queuing depth (if supported)
-r get/set readonly flag (DANGEROUS to set)
USE_FEATURE_HDPARM_HDIO_SCAN_HWIF(" -R register an IDE interface (DANGEROUS)
") B<-S> set standby (spindown) timeout
-t perform device read timings
-T perform cache read timings
-u get/set unmaskirq flag (0/1)
USE_FEATURE_HDPARM_HDIO_UNREGISTER_HWIF(" -U un-register an IDE interface (DANGEROUS)
") B<-v> defaults; same as B<-mcudkrag> for IDE drives
-V display program version and exit immediately
USE_FEATURE_HDPARM_HDIO_DRIVE_RESET(" -w perform device reset (DANGEROUS)
") B<-W> set drive write-caching flag (0/1) (DANGEROUS)
USE_FEATURE_HDPARM_HDIO_TRISTATE_HWIF(" -x tristate device for hotswap (0/1) (DANGEROUS)
") B<-X> set IDE xfer mode (DANGEROUS)
-y put IDE drive in standby mode
-Y put IDE drive to sleep
-Z disable Seagate auto-powersaving mode
-z re-read partition table
head
head [OPTION]... [FILE]...
Print first 10 lines of each FILE to standard output. With more than one FILE, precede each with a header
giving the file name. With no FILE, or when FILE is -, read standard input.
Options:
-n NUM Print first NUM lines instead of first 10 USE_FEATURE_FANCY_HEAD(
-c NUM output the first NUM bytes
-q never output headers giving file names
-v always output headers giving file names" )
Example:
$ head -n 2 /etc/passwd
root:x:0:0:root:/root:/bin/bash
daemon:x:1:1:daemon:/usr/sbin:/bin/sh
hexdump
hexdump [-[bcCdefnosvx]] [OPTION] FILE
The hexdump utility is a filter which displays the specified files, or the standard input, if no files are
specified, 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 byte
-v display all input data
-x Two-byte hexadecimal display
hostid
hostid
Print out a unique 32-bit identifier for the machine.
hostname
hostname [OPTION] {hostname | -F FILE}
Get or set the hostname or DNS domain name. If a hostname is given (or FILE with the -F parameter), the host
name will be set.
Options:
-s Short
-i Addresses for the hostname
-d DNS domain name
-f Fully qualified domain name
-F FILE Use the contents of FILE to specify the hostname
Example:
$ hostname
sage
httpd
httpd [-c <conf file>] USE_FEATURE_HTTPD_WITHOUT_INETD(" [-p <port>]") USE_FEATURE_HTTPD_SETUID("
[-u user]") USE_FEATURE_HTTPD_BASIC_AUTH(" [-r <realm>]") USE_FEATURE_HTTPD_AUTH_MD5(" [-m pass]") [-h
home] [-d/-e <string>]
Listens for incoming http server requests.
Options:
-c FILE Specifies configuration file. (default httpd.conf)
USE_FEATURE_HTTPD_WITHOUT_INETD(" -p PORT Server port (default 80)
") USE_FEATURE_HTTPD_SETUID(" B<-u> USER Set uid to USER after listening privileges port
") USE_FEATURE_HTTPD_BASIC_AUTH(" B<-r> REALM Authentication Realm for Basic Authentication
") USE_FEATURE_HTTPD_AUTH_MD5(" B<-m> PASS Crypt PASS with md5 algorithm
") B<-h> HOME Specifies http HOME directory (default ./)
-e STRING Html encode STRING
-d STRING URL decode STRING
hwclock
hwclock [-r|--show] [-s|--hctosys] [-w|--systohc] [-l|--localtime] [-u|--utc]
Query and set the hardware clock (RTC)
Options:
-r read hardware clock and print result
-s set the system time from the hardware clock
-w set the hardware clock to the current system time
-u the hardware clock is kept in coordinated universal time
-l the hardware clock is kept in local time
id id [OPTIONS]... [USERNAME]
Print information for USERNAME or the current user
Options:
-c prints only the security context
-g prints only the group ID
-u prints only the user ID
-n print a name instead of a number
-r prints the real user ID instead of the effective ID
Example:
$ id
uid=1000(andersen) gid=1000(andersen)
ifconfig
ifconfig [-a] <interface> [<address>]
configure a network interface
Options:
[add <address>[/<prefixlen>]]
[del <address>[/<prefixlen>]]
[[-]broadcast [<address>]] [[-]pointopoint [<address>]]
[netmask <address>] [dstaddr <address>]
[outfill <NN>] [keepalive <NN>]
[hw ether <address>] [metric <NN>] [mtu <NN>]
[[-]trailers] [[-]arp] [[-]allmulti]
[multicast] [[-]promisc] [txqueuelen <NN>] [[-]dynamic]
[mem_start <NN>] [io_addr <NN>] [irq <NN>]
[up|down] ...
ifdown
ifdown <-ahinv> <ifaces...>
ifdown <options> <ifaces...>
Options:
-h this help
-a de/configure all interfaces automatically
-i FILE use FILE for interface definitions
-n print out what would happen, but don't do it
(note that this option doesn't disable mappings)
-v print out what would happen before doing it
-m don't run any mappings
-f force de/configuration
ifup
ifup <-ahinv> <ifaces...>
ifup <options> <ifaces...>
Options:
-h this help
-a de/configure all interfaces automatically
-i FILE use FILE for interface definitions
-n print out what would happen, but don't do it
(note that this option doesn't disable mappings)
-v print out what would happen before doing it
-m don't run any mappings
-f force de/configuration
inetd
inetd [-f] [-q len] [conf]
Listens for network connections and launches programs
Option:
-f Run as a foreground progress
-q Sets the size of the socket listen queue to
the specified value. Default is 128
init
init
Init is the parent of all processes.
This version of init is designed to be run only by the kernel.
BusyBox init doesn't support multiple runlevels. The runlevels field of the /etc/inittab file is completely
ignored by BusyBox init. If you want runlevels, use sysvinit.
BusyBox init works just fine without an inittab. If no inittab is found, it has the following default behav-
ior:
::sysinit:/etc/init.d/rcS
::askfirst:/bin/sh
::ctrlaltdel:/sbin/reboot
::shutdown:/sbin/swapoff -a
::shutdown:/bin/umount -a -r
::restart:/sbin/init
if it detects that /dev/console is _not_ a serial console, it will also run:
tty2::askfirst:/bin/sh
tty3::askfirst:/bin/sh
tty4::askfirst:/bin/sh
If you choose to use an /etc/inittab file, the inittab entry format is as follows:
<id>:<runlevels>:<action>:<process>
<id>:
WARNING: This field has a non-traditional meaning for BusyBox init!
The id field is used by BusyBox init to specify the controlling tty for
the specified process to run on. The contents of this field are
appended to "/dev/" and used as-is. There is no need for this field to
be unique, although if it isn't you may have strange results. If this
field is left blank, the controlling tty is set to the console. Also
note that if BusyBox detects that a serial console is in use, then only
entries whose controlling tty is either the serial console or /dev/null
will be run. BusyBox init does nothing with utmp. We don't need no
stinkin' utmp.
<runlevels>:
The runlevels field is completely ignored.
<action>:
Valid actions include: sysinit, respawn, askfirst, wait,
once, restart, ctrlaltdel, and shutdown.
The available actions can be classified into two groups: actions
that are run only once, and actions that are re-run when the specified
process exits.
Run only-once actions:
'sysinit' is the first item run on boot. init waits until all
sysinit actions are completed before continuing. Following the
completion of all sysinit actions, all 'wait' actions are run.
'wait' actions, like 'sysinit' actions, cause init to wait until
the specified task completes. 'once' actions are asynchronous,
therefore, init does not wait for them to complete. 'restart' is
the action taken to restart the init process. By default this should
simply run /sbin/init, but can be a script which runs pivot_root or it
can do all sorts of other interesting things. The 'ctrlaltdel' init
actions are run when the system detects that someone on the system
console has pressed the CTRL-ALT-DEL key combination. Typically one
wants to run 'reboot' at this point to cause the system to reboot.
Finally the 'shutdown' action specifies the actions to taken when
init is told to reboot. Unmounting filesystems and disabling swap
is a very good here
Run repeatedly actions:
'respawn' actions are run after the 'once' actions. When a process
started with a 'respawn' action exits, init automatically restarts
it. Unlike sysvinit, BusyBox init does not stop processes from
respawning out of control. The 'askfirst' actions acts just like
respawn, except that before running the specified process it
displays the line "Please press Enter to activate this console."
and then waits for the user to press enter before starting the
specified process.
Unrecognized actions (like initdefault) will cause init to emit an
error message, and then go along with its business. All actions are
run in the order they appear in /etc/inittab.
<process>:
Specifies the process to be executed and its command line.
Example /etc/inittab file:
# This is run first except when booting in single-user mode.
#
::sysinit:/etc/init.d/rcS
# /bin/sh invocations on selected ttys
#
# Start an "askfirst" shell on the console (whatever that may be)
::askfirst:-/bin/sh
# Start an "askfirst" shell on /dev/tty2-4
tty2::askfirst:-/bin/sh
tty3::askfirst:-/bin/sh
tty4::askfirst:-/bin/sh
# /sbin/getty invocations for selected ttys
#
tty4::respawn:/sbin/getty 38400 tty4
tty5::respawn:/sbin/getty 38400 tty5
# Example of how to put a getty on a serial line (for a terminal)
#
#::respawn:/sbin/getty -L ttyS0 9600 vt100
#::respawn:/sbin/getty -L ttyS1 9600 vt100
#
# Example how to put a getty on a modem line.
#::respawn:/sbin/getty 57600 ttyS2
# Stuff to do when restarting the init process
::restart:/sbin/init
# Stuff to do before rebooting
::ctrlaltdel:/sbin/reboot
::shutdown:/bin/umount -a -r
::shutdown:/sbin/swapoff -a
insmod
insmod [OPTION]... MODULE [symbol=value]...
Loads the specified kernel modules into the kernel.
Options:
-f Force module to load into the wrong kernel version
-k Make module autoclean-able
-v verbose output
-q quiet output
-L Lock to prevent simultaneous loads of a module
-m Output load map to stdout
-o NAME Set internal module name to NAME
-x do not export externs
install
install [-cgmops] [sources] <dest|directory>
Copies files and set attributes
Options:
-c copy the file, default
-d create directories
-g set group ownership
-m set permission modes
-o set ownership
-p preserve date
-s strip symbol tables
ip ip [ OPTIONS ] { address | link | route | tunnel } { COMMAND | help }
ip [ OPTIONS ] OBJECT { COMMAND | help } where OBJECT := { link | addr | route | tunnel } OPTIONS := {
-f[amily] { inet | inet6 | link } | -o[neline] }
ipaddr
ipaddr { {add|del} IFADDR dev STRING | {show|flush} [ dev STRING ] [ to PREFIX ] }
ipaddr {add|delete} IFADDR dev STRING ipaddr {show|flush} [ dev STRING ] [ scope SCOPE-ID ]
[ to PREFIX ] [ label PATTERN ]
IFADDR := PREFIX | ADDR peer PREFIX
[ broadcast ADDR ] [ anycast ADDR ]
[ label STRING ] [ scope SCOPE-ID ]
SCOPE-ID := [ host | link | global | NUMBER ]
ipcalc
ipcalc [OPTION]... <ADDRESS>[[/]<NETMASK>] [NETMASK]
Calculate IP network settings from a IP address
Options:
-b --broadcast Display calculated broadcast address
-n --network Display calculated network address
-m --netmask Display default netmask for IP X
-p --prefix Display the prefix for IP/NETMASK
-h --hostname Display first resolved host name
-s --silent Don't ever display error messages
ipcrm
ipcrm [-[MQS] key] [-[mqs] id]
The upper-case options MQS are used to remove a shared memory segment by an shmkey value. The lower-case
options mqs are used to remove a segment by shmid value.
-m | -M Remove the memory segment after the last detach
-q | -Q Remove the message queue
-s | -S Remove the semaphore
ipcs
ipcs [[-smq] -i shmid] | [[-asmq] [-tclup]]
-i specify a specific resource id
Resource specification:
-m shared memory segments
-q message queues
-s semaphore arrays
-a all (default)
Output format:
-t time
-p pid
-s creator
-a limits
-i summary
iplink
iplink
iplink set DEVICE { up | down | arp { on | off } |
dynamic { on | off } |
mtu MTU }
iplink show [ DEVICE ]
iproute
iproute { list | flush | { add | del | change | append | replace | monitor } ROUTE }
iproute { list | flush } SELECTOR iproute get ADDRESS [ from ADDRESS iif STRING ]
[ oif STRING ] [ tos TOS ]
iproute { add | del | change | append | replace | monitor } ROUTE
SELECTOR := [ root PREFIX ] [ match PREFIX ] [ proto RTPROTO ]
ROUTE := [ TYPE ] PREFIX [ tos TOS ] [ proto RTPROTO ]
iptunnel
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 ]
kill
kill [-signal] process-id [process-id ...]
Send a signal (default is SIGTERM) to the specified process(es).
Options:
-l List all signal names and numbers
Example:
$ ps | grep apache
252 root root S [apache]
263 www-data www-data S [apache]
264 www-data www-data S [apache]
265 www-data www-data S [apache]
266 www-data www-data S [apache]
267 www-data www-data S [apache]
$ kill 252
killall
killall [-q] [-signal] process-name [process-name ...]
Send a signal (default is SIGTERM) to the specified process(es).
Options:
-l List all signal names and numbers
-q Do not complain if no processes were killed
Example:
$ killall apache
klogd
klogd [-c n] [-n]
Kernel logger. Options:
-c n Sets the default log level of console messages to n
-n Run as a foreground process
lash
lash [FILE]... or: sh -c command [args]...
The BusyBox LAme SHell (command interpreter)
This command does not yet have proper documentation.
Use lash just as you would use any other shell. It properly handles pipes, redirects, job control, can be
used as the shell for scripts, and has a sufficient set of builtins to do what is needed. It does not (yet)
support Bourne Shell syntax. If you need things like "if-then-else", "while", and such use ash or bash. If
you just need a very simple and extremely small shell, this will do the job.
last
last
Shows listing of the last users that logged into the system
length
length STRING
Prints out the length of the specified STRING.
Example:
$ length Hello
5
less
less [-EMNmh~?] FILE1 FILE2...
View a file or list of files. The position within files can be changed, and files can be manipulated in vari-
ous ways with the following options:
-E Quit once the end of a file is reached
-M Display a status line containing the current line numbers
and the percentage through the file
-N Prefix line numbers to each line
-m Display a status line containing the percentage through the
file
-~ Suppress ~s displayed when input past the end of the file is
reached.
-h, -? Display this help message
ln ln [OPTION] TARGET... LINK_NAME|DIRECTORY
Create a link named LINK_NAME or DIRECTORY to the specified TARGET
You may use '--' to indicate that all following arguments are non-options.
Options:
-s make symbolic links instead of hard links
-f remove existing destination files
-n no dereference symlinks - treat like normal file
-b make a backup of the target (if exists) before link operation
-S suffix use suffix instead of ~ when making backup files
Example:
$ ln -s BusyBox /tmp/ls
$ ls -l /tmp/ls
lrwxrwxrwx 1 root root 7 Apr 12 18:39 ls -> BusyBox*
loadfont
loadfont < font
Loads a console font from standard input.
Example:
$ loadfont < /etc/i18n/fontname
loadkmap
loadkmap < keymap
Loads a binary keyboard translation table from standard input.
Example:
$ loadkmap < /etc/i18n/lang-keymap
logger
logger [OPTION]... [MESSAGE]
Write MESSAGE to the system log. If MESSAGE is omitted, log stdin.
Options:
-s Log to stderr as well as the system log
-t TAG Log using the specified tag (defaults to user name)
-p PRIORITY Enter the message with the specified priority
This may be numerical or a ``facility.level pair
Example:
$ logger "hello"
login
login [OPTION]... [username] [ENV=VAR ...]
Begin a new session on the system
Options:
-f Do not authenticate (user already authenticated)
-h Name of the remote host for this login
-p Preserve environment
logname
logname
Print the name of the current user.
Example:
$ logname
root
logread
logread [OPTION]...
Shows the messages from syslogd (using circular buffer).
Options:
-f output data as the log grows
losetup
losetup [-od] LOOPDEVICE [FILE]
Associate LOOPDEVICE with FILE, or display current association.
Options:
-d Disassociate LOOPDEVICE
-o OFFSET Start OFFSET bytes into FILE
One argument (losetup /dev/loop1) will display the current association (if any), or disassociate it (with
-d). The display shows the offset and filename of the file the loop device is currently bound to.
Two arguments (losetup /dev/loop1 file.img) create a new association, with an optional offset (-o 12345).
Encryption is not yet supported.
ls ls [-1AacCdeFilnpLRrSsTtuvwxX" USE_FEATURE_HUMAN_READABLE("h") "kK] [filenames...]
List directory contents
Options:
-1 list files in a single column
-A do not list implied . and ..
-a do not hide entries starting with .
-C list entries by columns
-c with -l: show ctime
--color[={always,never,auto}] to control coloring
-d list directory entries instead of contents
-e list both full date and full time
-F append indicator (one of */=@|) to entries
-i list the i-node for each file
-l use a long listing format
-n list numeric UIDs and GIDs instead of names
-p append indicator (one of /=@|) to entries
-L list entries pointed to by symbolic links
-R list subdirectories recursively
-r sort the listing in reverse order
-S sort the listing by file size
-s list the size of each file, in blocks
-T NUM assume Tabstop every NUM columns
-t with -l: show modification time
-u with -l: show access time
-v sort the listing by version
-w NUM assume the terminal is NUM columns wide
-x list entries by lines instead of by columns
-X sort the listing by extension
USE_FEATURE_HUMAN_READABLE( -h print sizes in human readable format (e.g., 1K 243M 2G )
") B<-k> print security context
-K print security context in long format
lsattr
lsattr [-Radlv] [files...]
list file attributes on an ext2 fs
Options:
-R recursively list subdirectories
-a do not hide entries starting with .
-d list directory entries instead of contents
-l print long flag names
-v list the file's version/generation number
lsmod
lsmod
List the currently loaded kernel modules.
lzmacat
lzmacat FILE
Uncompress to stdout.
makedevs
makedevs [-d device_table] rootdir
Creates a range of special files as specified in a device table. Device table entries take the form of:
<type> <mode> <uid> <gid> <major> <minor> <start> <inc> <count> Where name is the file name, type can be one
of:
f A regular file
d Directory
c Character special device file
b Block special device file
p Fifo (named pipe)
uid is the user id for the target file, gid is the group id for the
target file. The rest of the entries (major, minor, etc) apply to
to device special files. A '-' may be used for blank entries.
Example:
For example:
<name> <type> <mode><uid><gid><major><minor><start><inc><count>
/dev d 755 0 0 - - - - -
/dev/console c 666 0 0 5 1 - - -
/dev/null c 666 0 0 1 3 0 0 -
/dev/zero c 666 0 0 1 5 0 0 -
/dev/hda b 640 0 0 3 0 0 0 -
/dev/hda b 640 0 0 3 1 1 1 15
Will Produce:
/dev
/dev/console
/dev/null
/dev/zero
/dev/hda
/dev/hda[0-15]
md5sum
md5sum [OPTION] [FILEs...]
or: md5sum [OPTION] -c [FILE]
Print or check MD5 checksums.
Options: With no FILE, or when FILE is -, read standard input.
-c check MD5 sums against given list
The following two options are useful only when verifying checksums:
-s don't output anything, status code shows success
-w warn about improperly formated MD5 checksum lines
Example:
$ md5sum < busybox
6fd11e98b98a58f64ff3398d7b324003
$ md5sum busybox
6fd11e98b98a58f64ff3398d7b324003 busybox
$ md5sum -c -
6fd11e98b98a58f64ff3398d7b324003 busybox
busybox: OK
^D
mdev
mdev [-s]
-s Scan /sys and populate /dev during system boot
Called with no options (via hotplug) it uses environment variables to determine which device to add/remove.
USE_FEATURE_MDEV_CONFIG( The mdev config file contains lines that look like:
hd[a-z][0-9]* 0:3 660
That's device name (with regex match), uid:gid, and permissions.
USE_FEATURE_MDEV_EXEC( Optionally, that can be followed (on the same line) by a special character
and a command line to run after creating/before deleting the corresponding
device(s). The environment variable $MDEV indicates the active device node
(which is useful if it's a regex match). For example:
hdc root:cdrom 660 *ln -s $MDEV cdrom
The special characters are @ (run after creating), $ (run before deleting), and * (run both after creating
and before deleting). The commands run in the /dev directory, and use system() which calls /bin/sh.
) Config file parsing stops on the first matching line. If no config
entry is matched, devices are created with default 0:0 660. (Make
the last line match .* to override this.)
)
mesg
mesg [y|n]
mesg controls write access to your terminal
y Allow write access to your terminal
n Disallow write access to your terminal
mkdir
mkdir [OPTION] DIRECTORY...
Create the DIRECTORY(ies) if they do not already exist
Options:
-m set permission mode (as in chmod), not rwxrwxrwx - umask
-p no error if existing, make parent directories as needed
Example:
$ mkdir /tmp/foo
$ mkdir /tmp/foo
/tmp/foo: File exists
$ mkdir /tmp/foo/bar/baz
/tmp/foo/bar/baz: No such file or directory
$ mkdir -p /tmp/foo/bar/baz
mke2fs
mke2fs [-c|-l filename] [-b block-size] [-f fragment-size] [-g blocks-per-group] [-i bytes-per-inode]
[-j] [-J journal-options] [-N number-of-inodes] [-n] [-m reserved-blocks-percentage] [-o creator-os] [-O fea-
ture[,...]] [-q] [r fs-revision-level] [-E extended-options] [-v] [-F] [-L volume-label] [-M
last-mounted-directory] [-S] [-T filesystem-type] device [blocks-count]
-b size block size in bytes
-c check for bad blocks before creating
-E opts set extended options
-f size fragment size in bytes
-F force (ignore sanity checks)
-g num number of blocks in a block group
-i ratio the bytes/inode ratio
-j create a journal (ext3)
-J opts set journal options (size/device)
-l file read bad blocks list from file
-L lbl set the volume label
-m percent percent of fs blocks to reserve for admin
-M dir set last mounted directory
-n do not actually create anything
-N num number of inodes to create
-o os set the 'creator os' field
-O features dir_index/filetype/has_journal/journal_dev/sparse_super
-q quiet execution
-r rev set filesystem revision
-S write superblock and group descriptors only
-T fs-type set usage type (news/largefile/largefile4)
-v verbose execution
mkfifo
mkfifo [OPTIONS] name
Creates a named pipe (identical to 'mknod name p')
Options:
-m create the pipe using the specified mode (default a=rw)
mkfs.minix
mkfs.minix [-c | -l filename] [-nXX] [-iXX] /dev/name [blocks]
Make a MINIX filesystem.
Options:
-c Check the device for bad blocks
-n [14|30] Specify the maximum length of filenames
-i INODES Specify the number of inodes for the filesystem
-l FILENAME Read the bad blocks list from FILENAME
-v Make a Minix version 2 filesystem
mknod
mknod [OPTIONS] NAME TYPE MAJOR MINOR
Create a special file (block, character, or pipe).
Options:
-m create the special file using the specified mode (default a=rw)
TYPEs include:
b: Make a block (buffered) device
c or u: Make a character (un-buffered) device
p: Make a named pipe. MAJOR and MINOR are ignored for named pipes
Example:
$ mknod /dev/fd0 b 2 0
$ mknod -m 644 /tmp/pipe p
mkswap
mkswap [-c] [-v0|-v1] device [block-count]
Prepare a disk partition to be used as a swap partition.
Options:
-c Check for read-ability
-v0 Make version 0 swap [max 128 Megs]
-v1 Make version 1 swap [big!] (default for kernels >
2.1.117)
block-count Number of block to use (default is entire partition)
mktemp
mktemp [-dq] TEMPLATE
Creates a temporary file with its name based on TEMPLATE. TEMPLATE is any name with six `Xs' (i.e.,
/tmp/temp.XXXXXX).
Options:
-d Make a directory instead of a file
-q Fail silently if an error occurs
Example:
$ mktemp /tmp/temp.XXXXXX
/tmp/temp.mWiLjM
$ ls -la /tmp/temp.mWiLjM
-rw------- 1 andersen andersen 0 Apr 25 17:10 /tmp/temp.mWiLjM
modprobe
modprobe [-knqrsv] MODULE [symbol=value ...]
Options:
-k Make module autoclean-able
-n Just show what would be done
-q Quiet output
-r Remove module (stacks) or do autoclean
-s Report via syslog instead of stderr
-v Verbose output
modprobe can (un)load a stack of modules, passing each module options (when loading). modprobe uses a config-
uration file to determine what option(s) to pass each module it loads.
The configuration file is searched (in order) amongst:
/etc/modprobe.conf (2.6 only)
/etc/modules.conf
/etc/conf.modules (deprecated)
They all have the same syntax (see below). If none is present, it is _not_ an error; each loaded module is
then expected to load without options. Once a file is found, the others are tested for.
/etc/modules.conf entry format:
alias <alias_name> <mod_name>
Makes it possible to modprobe alias_name, when there is no such module.
It makes sense if your mod_name is long, or you want a more representative
name for that module (eg. 'scsi' in place of 'aha7xxx').
This makes it also possible to use a different set of options (below) for
the module and the alias.
A module can be aliased more than once.
options <mod_name|alias_name> <symbol=value ...>
When loading module mod_name (or the module aliased by alias_name), pass
the "symbol=value" pairs as option to that module.
Sample /etc/modules.conf file:
options tulip irq=3
alias tulip tulip2
options tulip2 irq=4 io=0x308
Other functionality offered by 'classic' modprobe is not available in this implementation.
If module options are present both in the config file, and on the command line, then the options from the
command line will be passed to the module _after_ the options from the config file. That way, you can have
defaults in the config file, and override them for a specific usage from the command line.
Example:
(with the above /etc/modules.conf):
$ modprobe tulip
will load the module 'tulip' with default option 'irq=3'
$ modprobe tulip irq=5
will load the module 'tulip' with option 'irq=5', thus overriding the default
$ modprobe tulip2
will load the module 'tulip' with default options 'irq=4 io=0x308',
which are the default for alias 'tulip2'
$ modprobe tulip2 irq=8
will load the module 'tulip' with default options 'irq=4 io=0x308 irq=8',
which are the default for alias 'tulip2' overridden by the option 'irq=8'
from the command line
$ modprobe tulip2 irq=2 io=0x210
will load the module 'tulip' with default options 'irq=4 io=0x308 irq=4 io=0x210',
which are the default for alias 'tulip2' overridden by the options 'irq=2 io=0x210'
from the command line
more
more [FILE ...]
More is a filter for viewing FILE one screenful at a time.
Example:
$ dmesg | more
mount
mount [flags] DEVICE NODE [-o options,more-options]
Mount a filesystem. Filesystem autodetection requires /proc be mounted.
Flags:
-a: Mount all filesystems in fstab
-f: "Fake" Add entry to mount table but don't mount it
-n: Don't write a mount table entry
-o option: One of many filesystem options, listed below
-r: Mount the filesystem read-only
-t fs-type: Specify the filesystem type
-w: Mount for reading and writing (default)
Options for use with the "-o" flag:
async/sync: Writes are asynchronous / synchronous
atime/noatime: Enable / disable updates to inode access times
dev/nodev: Allow use of special device files / disallow them
exec/noexec: Allow use of executable files / disallow them
loop: Ignored (loop devices are autodetected)
suid/nosuid: Allow set-user-id-root programs / disallow them
remount: Re-mount a mounted filesystem, changing its flags
ro/rw: Mount for read-only / read-write
bind: Bind a directory to an additional location
move: Relocate an existing mount point.
There are EVEN MORE flags that are specific to each filesystem You'll have to see the written documentation
for those filesystems
Returns 0 for success, number of failed mounts for -a, or errno for one mount.
Example:
$ mount
/dev/hda3 on / type minix (rw)
proc on /proc type proc (rw)
devpts on /dev/pts type devpts (rw)
$ mount /dev/fd0 /mnt -t msdos -o ro
$ mount /tmp/diskimage /opt -t ext2 -o loop
$ mount cd_image.iso mydir
mountpoint
mountpoint [-q] <[-d] DIR | -x DEVICE>
mountpoint checks if the directory is a mountpoint
Options:
-q: Be more quiet
-d: Print major/minor device number of the filesystem
-x: Print major/minor device number of the blockdevice
Example:
$ mountpoint /proc
/proc is not a mountpoint
$ mountpoint /sys
/sys is a mountpoint
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 [OPTION]... SOURCE DEST or: mv [OPTION]... SOURCE... DIRECTORY
Rename SOURCE to DEST, or move SOURCE(s) to DIRECTORY.
Options:
-f don't prompt before overwriting
-i interactive, prompt before overwrite
Example:
$ mv /tmp/foo /bin/bar
nameif
nameif [-s] [-c FILE] [{IFNAME MACADDR}]
Nameif renaming network interface while it in the down state.
Options:
-c FILE Use configuration file (default is /etc/mactab)
-s Use syslog (LOCAL0 facility)
IFNAME MACADDR new_interface_name interface_mac_address
Example:
$ nameif -s dmz0 00:A0:C9:8C:F6:3F
or
$ nameif -c /etc/my_mactab_file
nc nc [OPTIONS] [IP] [port]
Netcat opens a pipe to IP:port
Options:
-l listen mode, for inbound connects
-p PORT local port number
-i SECS delay interval for lines sent
-e PROG program to exec after connect (dangerous!)
-w SECS timeout for connects and final net reads
Example:
$ nc foobar.somedomain.com 25
220 foobar ESMTP Exim 3.12 #1 Sat, 15 Apr 2000 00:03:02 -0600
help
214-Commands supported:
214- HELO EHLO MAIL RCPT DATA AUTH
214 NOOP QUIT RSET HELP
quit
221 foobar closing connection
netstat
netstat [-laenrtuwx]
Netstat displays Linux networking information.
Options:
-l display listening server sockets
-a display all sockets (default: connected)
-e display other/more information
-n don't resolve names
-r display routing table
-t tcp sockets
-u udp sockets
-w raw sockets
-x unix sockets
nice
nice [-n ADJUST] [COMMAND [ARG] ...]
Nice runs a program with modified scheduling priority.
Options:
-n ADJUST Adjust the scheduling priority by ADJUST
nohup
nohup COMMAND [ARGS]
run a command immune to hangups, with output to a non-tty
Example:
$ nohup make &
nslookup
nslookup [HOST] [SERVER]
Queries the nameserver for the IP address of the given HOST optionally using a specified DNS server
Example:
$ nslookup localhost
Server: default
Address: default
Name: debian
Address: 127.0.0.1
od od [-aBbcDdeFfHhIiLlOovXx] [FILE]
Write an unambiguous representation, octal bytes by default, of FILE to standard output. With no FILE, or
when FILE is -, read standard input.
openvt
openvt <vtnum> <COMMAND> [ARGS...]
Start a command on a new virtual terminal
Example:
openvt 2 /bin/ash
passwd
passwd [OPTION] [name]
Change a user password. If no name is specified, changes the password for the current user. Options:
-a Define which algorithm shall be used for the password
(Choices: des, md5 PASSWORD_ALG_TYPES(", sha1") )
-d Delete the password for the specified user account
-l Locks (disables) the specified user account
-u Unlocks (re-enables) the specified user account
patch
patch [-p<num>] [-i <diff>]
-p <num> Strip <num> leading components from file names
-i <diff> Read <diff> instead of stdin
Example:
$ patch -p1 < example.diff
$ patch -p0 -i example.diff
pidof
pidof process-name [OPTION] [process-name ...]
Lists the PIDs of all processes with names that match the names on the command line.
USAGE_PIDOF
-s display only a single PID
-o omit given pid.
Use %PPID to omit the parent pid of pidof itself
Example:
$ pidof init
1
$ pidof /bin/sh
20351 5973 5950
$ pidof /bin/sh -o %PPID
20351 5950
ping
ping [OPTION]... host
Send ICMP ECHO_REQUEST packets to network hosts.
Options:
-c COUNT Send only COUNT pings
-s SIZE Send SIZE data bytes in packets (default=56)
-q Quiet mode, only displays output at start
and when finished
Example:
$ ping localhost
PING slag (127.0.0.1): 56 data bytes
64 bytes from 127.0.0.1: icmp_seq=0 ttl=255 time=20.1 ms
--- debian ping statistics ---
1 packets transmitted, 1 packets received, 0% packet loss
round-trip min/avg/max = 20.1/20.1/20.1 ms
ping6
ping6 [OPTION]... host
Send ICMP ECHO_REQUEST packets to network hosts.
Options:
-c COUNT Send only COUNT pings
-s SIZE Send SIZE data bytes in packets (default=56)
-q Quiet mode, only displays output at start
and when finished
Example:
$ ping6 ip6-localhost
PING ip6-localhost (::1): 56 data bytes
64 bytes from ::1: icmp6_seq=0 ttl=64 time=20.1 ms
--- ip6-localhost ping statistics ---
1 packets transmitted, 1 packets received, 0% packet loss
round-trip min/avg/max = 20.1/20.1/20.1 ms
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<nosync>] [-f<force>]
Halt and shut off power. Options:
-d delay interval for halting
-n no call to sync()
-f force power off (don't go through init)
printenv
printenv [VARIABLES...]
print all or part of environment
If no environment VARIABLE specified, print them all.
printf
printf FORMAT [ARGUMENT...]
Formats and prints ARGUMENT(s) according to FORMAT, Where FORMAT controls the output exactly as in C printf.
Example:
$ printf "Val=%d\n" 5
Val=5
ps ps
Report process status
USAGE_PS
-c show SE Linux context
w wide output
Example:
$ ps
PID Uid Gid State Command
1 root root S init
2 root root S [kflushd]
3 root root S [kupdate]
4 root root S [kpiod]
5 root root S [kswapd]
742 andersen andersen S [bash]
743 andersen andersen S -bash
745 root root S [getty]
2990 andersen andersen R ps
pwd pwd
Print the full filename of the current working directory.
Example:
$ pwd
/root
rdate
rdate [-sp] HOST
Get and possibly set the system date and time from a remote HOST.
Options:
-s Set the system date and time (default)
-p Print the date and time
readlink
readlink [-f] FILE
Displays the value of a symbolic link.
Options:
-f canonicalize by following all symlinks
readprofile
readprofile [OPTIONS]...
Options:
-m <mapfile> (default: /boot/System.map)
-p <profile> (default: /proc/profile)
-M <mult> set the profiling multiplier to <mult>
-i print only info about the sampling step
-v print verbose data
-a print all symbols, even if count is 0
-b print individual histogram-bin counts
-s print individual counters within functions
-r reset all the counters (root only)
-n disable byte order auto-detection
realpath
realpath pathname ...
Returns the absolute pathnames of given argument.
reboot
reboot [-d<delay>] [-n<nosync>] [-f<force>]
Reboot the system. Options:
-d delay interval for rebooting
-n no call to sync()
-f force reboot (don't go through init)
renice
renice {{-n INCREMENT} | PRIORITY} [[ -p | -g | -u ] ID ...]
Changes priority of running processes.
Options:
-n adjusts 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
Resets the screen.
rm rm [OPTION]... FILE...
Remove (unlink) the FILE(s). You may use '--' to indicate that all following arguments are non-options.
Options:
-i always prompt before removing each destination
-f remove existing destinations, never prompt
-r or -R remove the contents of directories recursively
Example:
$ rm -rf /tmp/foo
rmdir
rmdir [OPTION]... DIRECTORY...
Remove the DIRECTORY(ies), if they are empty.
Example:
# rmdir /tmp/foo
rmmod
rmmod [OPTION]... [MODULE]...
Unloads the specified kernel modules from the kernel.
Options:
-a Remove all unused modules (recursively)
Example:
$ rmmod tulip
route
route [{add|del|delete}]
Edit the kernel's routing tables.
Options:
-n Dont resolve names
-e Display other/more information
-A inet{6} Select address family
rpm rpm -i -q[ildc]p package.rpm
Manipulates RPM packages
Options:
-i Install package
-q Query package
-p Query uninstalled package
-i Show information
-l List contents
-d List documents
-c List config files
rpm2cpio
rpm2cpio package.rpm
Outputs a cpio archive of the rpm file.
run-parts
run-parts [-t] [-a ARG] [-u MASK] DIRECTORY
Run a bunch of scripts in a directory.
Options:
-t Prints what would be run, but does not actually run anything
-a ARG Pass ARG as an argument for every program invoked
-u MASK Set the umask to MASK before executing every program
runlevel
runlevel [utmp]
Example:
$ runlevel /var/run/utmp
N 2
rx rx FILE
Receive a file using the xmodem protocol.
Example:
$ rx /tmp/foo
sed sed [-efinr] pattern [files...]
Options:
-e script add the script to the commands to be executed
-f scriptfile add script-file contents to the
commands to be executed
-i edit files in-place
-n suppress automatic printing of pattern space
-r use extended regular expression syntax
If no -e or -f is given, the first non-option argument is taken as the sed script to interpret. All remaining
arguments are names of input files; if no input files are specified, then the standard input is read. Source
files will not be modified unless -i option is given.
Example:
$ echo "foo" | sed -e 's/f[a-zA-Z]o/bar/g'
bar
seq seq [first [increment]] last
Print numbers from FIRST to LAST, in steps of INCREMENT. FIRST, INCREMENT default to 1 Arguments:
LAST
FIRST LAST
FIRST INCREMENT LAST
setarch
setarch <personality> <program> [args ...]
Personality may be:
linux32 Set 32bit uname emulation
linux64 Set 64bit uname emulation
setconsole
setconsole [-r|--reset] [DEVICE]
Redirects system console output to DEVICE (default: /dev/tty).
Options:
-r Reset output to /dev/console.
setkeycodes
setkeycodes SCANCODE KEYCODE ...
Set entries into the kernel's scancode-to-keycode map, allowing unusual keyboards to generate usable key-
codes.
SCANCODE may be either xx or e0xx (hexadecimal), and KEYCODE is given in decimal
Example:
$ setkeycodes e030 127
setlogcons
setlogcons N
Redirects the kernel output to console N (0 for current).
setsid
setsid program [arg ...]
Runs any program in a new session by calling setsid() before exec'ing the rest of its arguments. See set-
sid(2) for details.
sha1sum
sha1sum [OPTION] [FILEs...]
or: sha1sum [OPTION] -c [FILE]
Print or check SHA1 checksums.
Options: With no FILE, or when FILE is -, read standard input.
-c check SHA1 sums against given list
The following two options are useful only when verifying checksums:
-s don't output anything, status code shows success
-w warn about improperly formated SHA1 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.
Example:
$ sleep 2
[2 second delay results]
$ sleep 1d 3h 22m 8s
[98528 second delay results]
sort
sort [-nrugMcszbdfimSTokt] [-o outfile] [-k start[.offset][opts][,end[.offset][opts]] [-t char]
[FILE]...
Sorts lines of text in the specified files
Options:
-b ignore leading blanks
-c check whether input is sorted
-d dictionary order (blank or alphanumeric only)
-f ignore case
-g general numerical sort
-i ignore unprintable characters
-k specify sort key
-M sort month
-n sort numbers
-o output to file
-k sort by key
-t use key separator other than whitespace
-r reverse sort order
-s stable (don't sort ties alphabetically)
-u suppress duplicate lines
-z input terminated by nulls, not newlines
-mST ignored for GNU compatibility
Example:
$ echo -e "e\nf\nb\nd\nc\na" | sort
a
b
c
d
e
f
$ echo -e "c 3\nb 2\nd 2" | $SORT -k 2,2n -k 1,1r
d 2
b 2
c 3
start-stop-daemon
start-stop-daemon [OPTIONS] [--start|--stop] ... [-- arguments...]
Program to start and stop services.
Options:
-S|--start start
-K|--stop stop
-a|--startas <pathname> starts process specified by pathname
-b|--background force process into background
-u|--user <username>|<uid> stop this user's processes
-x|--exec <executable> program to either start or check
-m|--make-pidfile <filename> create the -p file and enter pid in it
-n|--name <process-name> stop processes with this name
-p|--pidfile <pid-file> save or load pid using a pid-file
-q|--quiet be quietUSE_FEATURE_START_STOP_DAEMON_FANCY(
-o|--oknodo exit status 0 if nothing done
-v|--verbose be verbose)
-s|--signal <signal> signal to send (default TERM)
stat
stat [OPTION] FILE...
display file (default) or filesystem status.
Options:
-c fmt use the specified format
-f display filesystem status
-L,-l dereference links
-t display info in terse form
Valid format sequences for files:
%a Access rights in octal
%A Access rights in human readable form
%b Number of blocks allocated (see %B)
%B The size in bytes of each block reported by %b
%d Device number in decimal
%D Device number in hex
%f Raw mode in hex
%F File type
%g Group ID of owner
%G Group name of owner
%h Number of hard links
%i Inode number
%n File name
%N Quoted file name with dereference if symbolic link
%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 transfers)
%S Fundamental block size (for block counts)
%t Type in hex
%T Type in human readable form
strings
strings [-afo] [-n length] [file ... ]
Display printable strings in a binary file.
Options:
-a Scan the whole files (this is the default).
-f Precede each string with the name of the file where it was found.
-n N Specifies that at least N characters forms a sequence (default 4)
-o Each string is preceded by its decimal offset in the file
stty
stty [-a|g] [-F DEVICE] [SETTING]...
Without arguments, prints baud rate, line discipline, and deviations from stty sane.
Options:
-F DEVICE open device instead of stdin
-a print all current settings in human-readable form
-g print in stty-readable form
[SETTING] see manpage
su su [OPTION]... [-] [username]
Change user id or become root. Options:
-p, -m Preserve environment
-c Command to pass to 'sh -c'
-s Shell to use instead of default shell
sulogin
sulogin [OPTION]... [tty-device]
Single user login Options:
-f Do not authenticate (user already authenticated)
-h Name of the remote host for this login
-p Preserve environment
sum sum [rs] [files...]
checksum and count the blocks in a file
Options:
-r use BSD sum algorithm (1K blocks)
-s use System V sum algorithm (512byte blocks)
swapoff
swapoff [-a] [DEVICE]
Stop swapping virtual memory pages on DEVICE.
Options:
-a Stop swapping on all swap devices
swapon
swapon [-a] [DEVICE]
Start swapping virtual memory pages on DEVICE.
Options:
-a Start swapping on all swap devices
switch_root
switch_root [-c /dev/console] NEW_ROOT NEW_INIT [ARGUMENTS_TO_INIT]
Use from PID 1 under initramfs to free initramfs, chroot to NEW_ROOT, and exec NEW_INIT.
Options:
-c Redirect console to device on new root
sync
sync
Write all buffered filesystem blocks to disk.
sysctl
sysctl [OPTIONS]... [VALUE]...
configure kernel parameters at runtime
Options:
-n Use this option to disable printing of the key name when printing values
-w Use this option when you want to change a sysctl setting
-p Load in sysctl settings from the file specified or /etc/sysctl.conf if none given
-a Display all values currently available
-A Display all values currently available in table form
Example:
sysctl [-n] variable ...
sysctl [-n] -w variable=value ...
sysctl [-n] -a
sysctl [-n] -p <file> (default /etc/sysctl.conf)
sysctl [-n] -A
syslogd
syslogd [OPTION]...
Linux system and kernel logging utility. Note that this version of syslogd ignores /etc/syslog.conf.
Options:
-m MIN Minutes between MARK lines (default=20, 0=off)
-n Run as a foreground process
-O FILE Use an alternate log file (default=/var/log/messages)
-S Make logging output smaller.
-s SIZE Max size (KB) before rotate (default=200KB, 0=off)
-b NUM Number of rotated logs to keep (default=1, max=99, 0=purge)
-R HOST[:PORT] Log to IP or hostname on PORT (default PORT=514/UDP)
-L Log locally and via network logging (default is network only)
-C [size(KiB)] Log to a circular buffer (read the buffer using logread)
Example:
$ syslogd -R masterlog:514
$ syslogd -R 192.168.1.1:601
tail
tail [OPTION]... [FILE]...
Print last 10 lines of each FILE to standard output. With more than one FILE, precede each with a header
giving the file name. With no FILE, or when FILE is -, read standard input.
Options:
-c N[kbm] output the last N bytes
-n N[kbm] print last N lines instead of last 10
-f output data as the file grows
-q never output headers giving file names
-s SEC wait SEC seconds between reads with -f
-v always output headers giving file names
If the first character of N (bytes or lines) is a '+', output begins with the Nth item from the start of each
file, otherwise, print the last N items in the file. N bytes may be suffixed by k (x1024), b (x512), or m
(1024^2).
Example:
$ tail -n 1 /etc/resolv.conf
nameserver 10.0.0.1
tar tar -[czjaZxtvO] [-X FILE][-f TARFILE] [-C DIR] [FILE(s)] ...
Create, extract, or list files from a tar file.
Options:
c create
x extract
t list
Archive format selection:
z Filter the archive through gzip
j Filter the archive through bzip2
a Filter the archive through lzma
Z Filter the archive through compress
File selection:
f name of TARFILE or "-" for stdin
O extract to stdout
exclude file to exclude
X file with names to exclude
C change to directory DIR before operation
v verbosely list files processed
Example:
$ zcat /tmp/tarball.tar.gz | tar -xf -
$ tar -cf /tmp/tarball.tar /usr/local
tee tee [OPTION]... [FILE]...
Copy standard input to each FILE, and also to standard output.
Options:
-a append to the given FILEs, do not overwrite
-i ignore interrupt signals (SIGINT)
Example:
$ echo "Hello" | tee /tmp/foo
$ cat /tmp/foo
Hello
telnet
telnet HOST [PORT]
Telnet is used to establish interactive communication with another computer over a network using the TELNET
protocol.
telnetd
telnetd [OPTION]
Telnetd listens for incoming TELNET connections on PORT. Options:
-p PORT listen for connections on PORT (default 23)
-l LOGIN exec LOGIN on connect (default /bin/sh)
-f issue_file Display issue_file instead of /etc/issue
test
test EXPRESSION
or [ EXPRESSION ]
Checks file types and compares values returning an exit code determined by the value of EXPRESSION.
Example:
$ test 1 -eq 2
$ echo $?
1
$ test 1 -eq 1
$ echo $?
0
$ [ -d /etc ]
$ echo $?
0
$ [ -d /junk ]
$ echo $?
1
tftp
tftp [OPTION]... HOST [PORT]
Transfers a file from/to a tftp server using "octet" mode.
Options:
-l FILE Local FILE
-r FILE Remote FILE
-g Get file
-p Put file
-b SIZE Transfer blocks of SIZE octets
time
time [OPTION]... COMMAND [ARGS...]
Runs the program COMMAND with arguments ARGS. When COMMAND finishes, COMMAND's resource usage information is
displayed
Options:
-v Displays verbose resource usage information
top top [-d <seconds>]
top provides an view of processor activity in real time. This utility reads the status for all processes in
/proc each <seconds> and shows the status for however many processes will fit on the screen. This utility
will not show processes that are started after program startup, but it wil