hush/docs/busybox.sgml
2000-07-08 00:09:30 +00:00

3580 lines
59 KiB
Plaintext

<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook V3.1//EN" [...]>
<book id="BusyBoxDocumentation">
<bookinfo>
<title>BusyBox - The Swiss Army Knife of Embedded Linux</title>
<legalnotice>
<para>
This documentation is free software; you can redistribute
it and/or modify it under the terms of the GNU General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later
version.
</para>
<para>
This program is distributed in the hope that it will be
useful, but WITHOUT ANY WARRANTY; without even the implied
warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
See the GNU General Public License for more details.
</para>
<para>
You should have received a copy of the GNU General Public
License along with this program; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
MA 02111-1307 USA
</para>
<para>
For more details see the file COPYING in the source
distribution of Linux.
</para>
</legalnotice>
</bookinfo>
<toc></toc>
<chapter id="Introduction">
<title>Introduction</title>
<para>
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 fileutils, shellutils, findutils, textutils,
grep, gzip, tar, etc. BusyBox provides a fairly complete POSIX environment
for any small or embedded system. 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.
</para>
<para>
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 a kernel, a
shell (such as ash), and an editor (such as elvis-tiny or ae).
</para>
</chapter>
<chapter id="Syntax">
<title>How to use BusyBox</title>
<sect1 id="How to use BusyBox">
<title>Syntax</title
<para>
<screen>
BusyBox &lt;function&gt; [arguments...] # or
</screen>
</para>
<para>
<screen>
&lt;function&gt; [arguments...] # if symlinked
</screen>
</para>
</sect1>
<sect1 id="Invoking BusyBox">
<para>
When you create a link to BusyBox for the function you wish to use, when
BusyBox is called using that link it will behave as if the command itself
has been invoked.
</para>
<para>
For example, entering
</para>
<para>
<screen>
ln -s ./BusyBox ls
./ls
</screen>
</para>
<para>
will cause BusyBox to behave as 'ls' (if the 'ls' command has been compiled
into BusyBox).
</para>
<para>
You can also invoke BusyBox by issuing the command as an argument on the
command line. For example, entering
</para>
<para>
<screen>
./BusyBox ls
</screen>
</para>
<para>
will also cause BusyBox to behave as 'ls'.
</para>
</sect1>
<sect1 id="Common options">
<para>
Most BusyBox commands support the <emphasis>--help</emphasis> option to provide
a terse runtime description of their behavior.
</para>
</sect1>
</chapter>
<chapter id="Commands">
<title>BusyBox Commands</title>
<sect1 id="Available BusyBox Commands">
<title>Available BusyBox Commands</title>
<para>
Currently defined functions include:
</para>
<para>
ar, basename, cat, chgrp, chmod, chown, chroot, chvt, clear, cp, cut, date,
dc, dd, deallocvt, df, dirname, dmesg, du, dutmp, echo, false, fbset,
fdflush, find, free, freeramdisk, fsck.minix, grep, gunzip, gzip, halt,
head, hostid, hostname, id, init, insmod, kill, killall, length, ln,
loadacm, loadfont, loadkmap, logger, logname, ls, lsmod, makedevs, mkdir,
mkfifo, mkfs.minix, mknod, mkswap, mktemp, more, mount, mt, mv, nc,
nslookup, ping, poweroff, printf, ps, pwd, reboot, rm, rmdir, rmmod, sed,
setkeycodes, sh, sleep, sort, swapoff, swapon, sync, syslogd, tail,
tar, tee, telnet, test, touch, tr, true, tty, umount, uname, uniq, update,
uptime, usleep, uudecode, uuencode, wc, which, whoami, yes, zcat, [
</para>
</sect1>
<sect1 id="ar">
<title>ar</title>
<para>
Usage: ar [OPTION] archive [FILENAME]...
</para>
<para>
Extract or list files from an ar archive.
</para>
<para>
Options:
</para>
<para>
<screen>
o Preserve original dates
p Extract to stdout
t List
x Extract
v Verbosely list files processed
</screen>
</para>
</sect1>
<sect1 id="basename">
<title>basename</title>
<para>
Usage: basename FILE [SUFFIX]
</para>
<para>
Strip directory path and suffixes from FILE. If specified, also removes
any trailing SUFFIX.
</para>
<para>
Example:
</para>
<para>
<screen>
$ basename /usr/local/bin/foo
foo
$ basename /usr/local/bin/
bin
$ basename /foo/bar.txt .txt
bar
</screen>
</para>
</sect1>
<sect1 id="cat">
<title>cat</title>
<para>
Usage: cat [FILE]...
</para>
<para>
Concatenate <literal>FILE(s)</literal> and prints them to the standard
output.
</para>
<para>
Example:
</para>
<para>
<screen>
$ cat /proc/uptime
110716.72 17.67
</screen>
</para>
</sect1>
<sect1 id="chgrp">
<title>chgrp</title>
<para>
Usage: chgrp [OPTION]... GROUP FILE...
</para>
<para>
Change the group membership of each FILE to GROUP.
</para>
<para>
Options:
</para>
<para>
<screen>
-R Change files and directories recursively
</screen>
</para>
<para>
Example:
</para>
<para>
<screen>
$ 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
</screen>
</para>
</sect1>
<sect1 id="chmod">
<title>chmod</title>
<para>
Usage: chmod [<emphasis>-R</emphasis>] MODE[,MODE]... FILE...
</para>
<para>
Change file access permissions for the specified
<literal>FILE(s)</literal> (or directories). Each MODE is defined by
combining the letters for WHO has access to the file, an OPERATOR for
selecting how the permissions should be changed, and a PERMISSION for
<literal>FILE(s)</literal> (or directories).
</para>
<para>
WHO may be chosen from
</para>
<para>
<screen>
u User who owns the file
g Users in the file's Group
o Other users not in the file's group
a All users
</screen>
</para>
<para>
OPERATOR may be chosen from
</para>
<para>
<screen>
+ Add a permission
- Remove a permission
= Assign a permission
</screen>
</para>
<para>
PERMISSION may be chosen from
</para>
<para>
<screen>
r Read
w Write
x Execute (or access for directories)
s Set user (or group) ID bit
t Sticky bit (for directories prevents removing files by non-owners)
</screen>
</para>
<para>
Alternately, permissions can be set numerically where the first three
numbers are calculated by adding the octal values, such as
</para>
<para>
<screen>
4 Read
2 Write
1 Execute
</screen>
</para>
<para>
An optional fourth digit can also be used to specify
</para>
<para>
<screen>
4 Set user ID
2 Set group ID
1 Sticky bit
</screen>
</para>
<para>
Options:
</para>
<para>
<screen>
-R Change files and directories recursively.
</screen>
</para>
<para>
Example:
</para>
<para>
<screen>
$ 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
</screen>
</para>
</sect1>
<sect1 id="chown">
<title>chown</title>
<para>
Usage: chown [OPTION]... OWNER[&lt;.|:&gt;[GROUP] FILE...
</para>
<para>
Change the owner and/or group of each FILE to OWNER and/or GROUP.
</para>
<para>
Options:
</para>
<para>
<screen>
-R Change files and directories recursively
</screen>
</para>
<para>
Example:
</para>
<para>
<screen>
$ 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
</screen>
</para>
</sect1>
<sect1 id="chroot">
<title>chroot</title>
<para>
Usage: chroot NEWROOT [COMMAND...]
</para>
<para>
Run COMMAND with root directory set to NEWROOT.
</para>
<para>
Example:
</para>
<para>
<screen>
$ ls -l /bin/ls
lrwxrwxrwx 1 root root 12 Apr 13 00:46 /bin/ls -&gt; /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*
</screen>
</para>
</sect1>
<sect1 id="chvt">
<title>chvt</title>
<para>
Usage: chvt N
</para>
<para>
Change the foreground virtual terminal to /dev/ttyN
</para>
</sect1>
<sect1 id="clear">
<title>clear</title>
<para>
Usage: clear
</para>
<para>
Clear the screen.
</para>
</sect1>
<sect1 id="cp">
<title>cp</title>
<para>
Usage: cp [OPTION]... SOURCE DEST
</para>
<para>
<screen>
or: cp [OPTION]... SOURCE... DIRECTORY
</screen>
</para>
<para>
Copy SOURCE to DEST, or multiple <literal>SOURCE(s)</literal> to
DIRECTORY.
</para>
<para>
Options:
</para>
<para>
<screen>
-a Same as -dpR
-d Preserve links
-p Preserve file attributes if possible
-R Copy directories recursively
</screen>
</para>
</sect1>
<sect1 id="cut">
<title>cut</title>
<para>
Usage: cut [OPTION]... [FILE]...
</para>
<para>
Print selected fields from each input FILE to standard output.
</para>
<para>
Options:
</para>
<para>
<screen>
-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 Only output Lines if the include DELIM
-f N Print only these fields
-n Ignored
</screen>
</para>
<para>
Example:
</para>
<para>
<screen>
$ echo "Hello world" | cut -f 1 -d ' '
Hello
$ echo "Hello world" | cut -f 2 -d ' '
world
</screen>
</para>
</sect1>
<sect1 id="date">
<title>date</title>
<para>
Usage: date [OPTION]... [+FORMAT]
</para>
<para>
<screen>
or: date [OPTION] [MMDDhhmm[[CC]YY][.ss]]
</screen>
</para>
<para>
Display the current time in the given FORMAT, or set the system date.
</para>
<para>
Options:
</para>
<para>
<screen>
-R Output RFC-822 compliant date string
-s Set time described by STRING
-u Print or set Coordinated Universal Time
</screen>
</para>
<para>
Example:
</para>
<para>
<screen>
$ date
Wed Apr 12 18:52:41 MDT 2000
</screen>
</para>
</sect1>
<sect1 id="dc">
<title>dc</title>
<para>
Usage: dc [EXPRESSION]
</para>
<para>
This is a Tiny RPN calculator that understands the
following operations: +, -, /, *, and, or, not, eor. If
no arguments are given, dc will process input from
stdin.
</para>
<para>
The behaviour of BusyBox/dc deviates (just a little ;-)
from GNU/dc, but this will be remedied in the future.
</para>
<para>
Example:
</para>
<para>
<screen>
$ dc 2 2 +
4
$ dc 8 8 \* 2 2 + /
16
$ dc 0 1 and
0
$ dc 0 1 or
1
$ echo 72 9 div 8 mul | dc
64
</screen>
</para>
</sect1>
<sect1 id="dd">
<title>dd</title>
<para>
Usage: dd [OPTION]...
</para>
<para>
Copy a file, converting and formatting according to
options.
</para>
<para>
Options:
</para>
<para>
<screen>
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
count=N Copy only N input blocks
skip=N Skip N input blocks
seek=N Skip N output blocks
</screen>
</para>
<para>
Numbers may be suffixed by w (x2), k (x1024), b (x512),
or M (x1024^2).
</para>
<para>
Example:
</para>
<para>
<screen>
$ dd if=/dev/zero of=/dev/ram1 bs=1M count=4
4+0 records in
4+0 records out
</screen>
</para>
</sect1>
<sect1 id="deallocvt">
<title>deallocvt</title>
<para>
Usage: deallocvt N
</para>
<para>
Deallocate unused virtual terminal /dev/ttyN.
</para>
</sect1>
<sect1 id="df">
<title>df</title>
<para>
Usage: df [FILE]...
</para>
<para>
Print the filesystem space used and space available.
</para>
<para>
Example:
</para>
<para>
<screen>
$ 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% /
</screen>
</para>
</sect1>
<sect1 id="dirname">
<title>dirname</title>
<para>
Usage: dirname NAME
</para>
<para>
Strip non-directory suffix from NAME.
</para>
<para>
Example:
</para>
<para>
<screen>
$ dirname /tmp/foo
/tmp
$ dirname /tmp/foo/
/tmp
</screen>
</para>
</sect1>
<sect1 id="dmesg">
<title>dmesg</title>
<para>
Usage: dmesg [OPTION]...
</para>
<para>
Print or control the kernel ring buffer.
</para>
<para>
Options:
</para>
<para>
<screen>
-c Clear the ring buffer after printing
-n LEVEL Set the console logging level to LEVEL
-s BUFSIZE Query ring buffer using a buffer of BUFSIZE
</screen>
</para>
</sect1>
<sect1 id="du">
<title>du</title>
<para>
Usage: du [OPTION]... [FILE]...
</para>
<para>
Summarize the disk space used for each FILE or current
directory. Disk space printed in units of 1k (i.e.
1024 bytes).
</para>
<para>
Options:
</para>
<para>
<screen>
-l Count sizes many times if hard linked
-s Display only a total for each argument
</screen>
</para>
<para>
Example:
</para>
<para>
<screen>
$ 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 .
</screen>
</para>
</sect1>
<sect1 id="dutmp">
<title>dutmp</title>
<para>
Usage: dutmp [FILE]
</para>
<para>
Dump utmp file format (pipe delimited) from FILE or
stdin to stdout.
</para>
<para>
Example:
</para>
<para>
<screen>
$ dutmp /var/run/utmp
8|7||si|||0|0|0|955637625|760097|0
2|0|~|~~|reboot||0|0|0|955637625|782235|0
1|20020|~|~~|runlevel||0|0|0|955637625|800089|0
8|125||l4|||0|0|0|955637629|998367|0
6|245|tty1|1|LOGIN||0|0|0|955637630|998974|0
6|246|tty2|2|LOGIN||0|0|0|955637630|999498|0
7|336|pts/0|vt00andersen|andersen|:0.0|0|0|0|955637763|0|0
</screen>
</para>
</sect1>
<sect1 id="echo">
<title>echo</title>
<para>
Usage: echo [OPTION]... [ARG]...
</para>
<para>
Print ARGs to stdout.
</para>
<para>
Options:
</para>
<para>
<screen>
-n Suppress trailing newline
-e Enable interpretation of escaped characters
-E Disable interpretation of escaped characters
</screen>
</para>
<para>
Example:
</para>
<para>
<screen>
$ echo "Erik is cool"
Erik is cool
$ echo -e "Erik\nis\ncool"
Erik
is
cool
$ echo "Erik\nis\ncool"
Erik\nis\ncool
</screen>
</para>
</sect1>
<sect1 id="false">
<title>false</title>
<para>
Usage: false
</para>
<para>
Return an exit code of FALSE (1).
</para>
<para>
Example:
</para>
<para>
<screen>
$ false
$ echo $?
1
</screen>
</para>
</sect1>
<sect1 id="fbset">
<title>fbset</title>
<para>
Usage: fbset [OPTION]... [MODE]
</para>
<para>
Show and modify frame buffer device settings.
</para>
<para>
Options:
</para>
<para>
<screen>
-h Display option summary
-fb DEVICE Operate on DEVICE
-db FILE Use FILE for mode database
-g XRES YRES VXRES VYRES DEPTH Set all geometry parameters
-t PIXCLOCK LEFT RIGHT UPPER LOWER HSLEN VSLEN Set all timing parameters
-xres RES Set visible horizontal resolution
-yres RES Set visible vertical resolution
</screen>
</para>
<para>
Example:
</para>
<para>
<screen>
$ 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
</screen>
</para>
</sect1>
<sect1 id="fdflush">
<title>fdflush</title>
<para>
Usage: fdflush DEVICE
</para>
<para>
Force floppy disk drive to detect disk change on DEVICE.
</para>
</sect1>
<sect1 id="find">
<title>find</title>
<para>
Usage: find [PATH]... [EXPRESSION]
</para>
<para>
Search for files in a directory hierarchy. The default
PATH is the current directory; default EXPRESSION is
'-print'.
</para>
<para>
EXPRESSION may consist of:
</para>
<para>
<screen>
-follow Dereference symbolic links
-name PATTERN File name (leading directories removed) matches PATTERN
-print Print the full file name followed by a newline to stdout
</screen>
</para>
<para>
Example:
</para>
<para>
<screen>
$ find / -name /etc/passwd
/etc/passwd
</screen>
</para>
</sect1>
<sect1 id="free">
<title>free</title>
<para>
Usage: free
</para>
<para>
Displays the amount of free and used system memory.
</para>
<para>
Example:
</para>
<para>
<screen>
$ free
total used free shared buffers
Mem: 257628 248724 8904 59644 93124
Swap: 128516 8404 120112
Total: 386144 257128 129016
</screen>
</para>
</sect1>
<sect1 id="freeramdisk">
<title>freeramdisk</title>
<para>
Usage: freeramdisk DEVICE
</para>
<para>
Free all memory used by the ramdisk DEVICE.
</para>
<para>
Example:
</para>
<para>
<screen>
$ freeramdisk /dev/ram2
</screen>
</para>
</sect1>
<sect1 id="fsck.minix">
<title>fsck.minix</title>
<para>
Usage: fsck.minix [OPTION]... DEVICE
</para>
<para>
Perform a consistency check on the MINIX filesystem on
DEVICE.
</para>
<para>
Options:
</para>
<para>
<screen>
-l List all filenames
-r Perform interactive repairs
-a Perform automatic repairs
-v Verbose
-s Output super-block information
-m Activate MINIX-like "mode not cleared" warnings
-f Force file system check.
</screen>
</para>
</sect1>
<sect1 id="grep">
<title>grep</title>
<para>
Usage: grep [OPTIONS]... PATTERN [FILE]...
</para>
<para>
Search for PATTERN in each FILE or stdin.
</para>
<para>
Options:
</para>
<para>
<screen>
-h Suppress the prefixing filename on output
-i Ignore case distinctions
-n Print line number with output lines
-q Be quiet. Returns 0 if result was found, 1 otherwise
-v Select non-matching lines
</screen>
</para>
<para>
This version of grep matches full regular expressions.
</para>
<para>
Example:
</para>
<para>
<screen>
$ 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
</screen>
</para>
</sect1>
<sect1 id="gunzip">
<title>gunzip</title>
<para>
Usage: gunzip [OPTION]... FILE
</para>
<para>
Uncompress FILE (or stdin if FILE is '-').
</para>
<para>
Options:
</para>
<para>
<screen>
-c Write output to standard output
-t Test compressed file integrity
</screen>
</para>
<para>
Example:
</para>
<para>
<screen>
$ 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
</screen>
</para>
</sect1>
< <sect1 id="gzip">
<title>gzip</title>
<para>
Usage: gzip [OPTION]... FILE
</para>
<para>
Compress FILE (or stdin if FILE is '-') with maximum
compression to FILE.gz (or stdout if FILE is '-').
</para>
<para>
Options:
</para>
<para>
<screen>
-c Write output to standard output
</screen>
</para>
<para>
Example:
</para>
<para>
<screen>
$ ls -la /tmp/BusyBox*
-rw-rw-r-- 1 andersen andersen 1761280 Apr 14 17:47 /tmp/BusyBox-0.43.tar
$ gzip /tmp/BusyBox-0.43.tar
$ ls -la /tmp/BusyBox*
-rw-rw-r-- 1 andersen andersen 554058 Apr 14 17:49 /tmp/BusyBox-0.43.tar.gz
</screen>
</para>
</sect1>
<sect1 id="halt">
<title>halt</title>
<para>
Usage: halt
</para>
<para>
Halt the system.
</para>
</sect1>
<sect1 id="head">
<title>head</title>
<para>
Usage: head [OPTION] FILE...
</para>
<para>
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.
</para>
<para>
Options:
</para>
<para>
<screen>
-n NUM Print first NUM lines instead of first 10
</screen>
</para>
<para>
Example:
</para>
<para>
<screen>
$ head -n 2 /etc/passwd
root:x:0:0:root:/root:/bin/bash
daemon:x:1:1:daemon:/usr/sbin:/bin/sh
</screen>
</para>
</sect1>
<sect1 id="hostid">
<title>hostid</title>
<para>
Usage: hostid
</para>
<para>
Prints out a unique 32-bit identifier for the current
machine. The 32-bit identifier is intended to be unique
among all UNIX systems in existence.
</para>
</sect1>
<sect1 id="hostname">
<title>hostname</title>
<para>
Usage: hostname [OPTION]... [HOSTNAME|-F FILE]
</para>
<para>
Get or set the hostname or DNS domain name. If a
hostname is given (or a file with the -F parameter), the
host name will be set.
</para>
<para>
Options:
</para>
<para>
<screen>
-s Short
-i Addresses for the hostname
-d DNS domain name
-F FILE Use the contents of FILE to specify the hostname
</screen>
</para>
<para>
Example:
</para>
<para>
<screen>
$ hostname
slag
</screen>
</para>
</sect1>
<sect1 id="id">
<title>id</title>
<para>
Usage: id [OPTION]... [USERNAME]
</para>
<para>
Print information for USERNAME or the current user.
</para>
<para>
Options:
</para>
<para>
<screen>
-g Print only the group ID
-u Print only the user ID
-r Print the real user ID instead of the effective ID (with -ug)
</screen>
</para>
<para>
Example:
</para>
<para>
<screen>
$ id
uid=1000(andersen) gid=1000(andersen)
</screen>
</para>
</sect1>
<sect1 id="init">
<title>init</title>
<para>
Usage: init
</para>
<para>
Init is the parent of all processes.
</para>
<para>
This version of init is designed to be run only by the
kernel.
</para>
<para>
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.
</para>
<para>
BusyBox init works just fine without an inittab. If no
inittab is found, it has the following default behavior:
</para>
<para>
<screen>
::sysinit:/etc/init.d/rcS
::askfirst:/bin/sh
</screen>
</para>
<para>
If it detects that /dev/console is _not_ a serial
console, it will also run:
</para>
<para>
<screen>
tty2::askfirst:/bin/sh
</screen>
</para>
<para>
If you choose to use an /etc/inittab file, the inittab
entry format is as follows:
</para>
<para>
<screen>
&lt;id&gt;:&lt;runlevels&gt;:&lt;action&gt;:&lt;process&gt;
</screen>
<para>
<sect2>
<title>id</title>
<para>
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,
it is completely ignored. Also note that if
BusyBox detects that a serial console is in use,
then all entries containing non-empty id fields
will _not_ be run. BusyBox init does nothing
with utmp. We don't need no stinkin' utmp.
</para>
</sect2>
<sect2>
<title>runlevels</title>
<para>
The runlevels field is completely ignored.
</para>
</sect2>
<sect2>
<title>action</title>
<para>
Valid actions include: sysinit, respawn,
askfirst, wait, once, and ctrlaltdel.
</para>
<para>
askfirst acts just like respawn, but 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.
</para>
<para>
Unrecognized actions (like initdefault) will
cause init to emit an error message, and then go
along with its business.
</para>
</sect2>
<sect2>
<title>process</title>
<para>
Specifies the process to be executed and its
command line.
</para>
</sect2>
<para>
Example /etc/inittab file:
</para>
<para>
<screen>
# 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
tty2::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)
#
#ttyS0::respawn:/sbin/getty -L ttyS0 9600 vt100
#ttyS1::respawn:/sbin/getty -L ttyS1 9600 vt100
#
# Example how to put a getty on a modem line.
#ttyS2::respawn:/sbin/getty -x0 -s 57600 ttyS2
# Stuff to do before rebooting
::ctrlaltdel:/bin/umount -a -r &gt; /dev/null 2&gt;&amp;1
::ctrlaltdel:/sbin/swapoff -a &gt; /dev/null 2&gt;&amp;1
</screen>
</para>
</sect1>
<sect1 id="insmod">
<title>insmod</title>
<para>
Usage: insmod [OPTION]... MODULE [symbol=value]...
</para>
<para>
Load MODULE into the kernel.
</para>
<para>
Options:
</para>
<para>
<screen>
-f Force module to load into the wrong kernel version.
-k Make module autoclean-able.
-v Verbose output
-x Do not export externs
</screen>
</para>
</sect1>
<sect1 id="kill">
<title>kill</title>
<para>
Usage: kill [OPTION] PID...
</para>
<para>
Send a signal (default is SIGTERM) to the specified
PID(s).
</para>
<para>
Options:
</para>
<para>
<screen>
-l List all signal names and numbers
-SIG Send signal SIG
</screen>
</para>
<para>
Example:
</para>
<para>
<screen>
$ 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
</screen>
</para>
</sect1>
<sect1 id="killall">
<title>killall</title>
<para>
Usage: killall [OPTION] NAME...
</para>
<para>
Send a signal (default is SIGTERM) to the specified
NAME(s).
</para>
<para>
Options:
</para>
<para>
<screen>
-l List all signal names and numbers
-SIG Send signal SIG
</screen>
</para>
<para>
Example:
</para>
<para>
<screen>
$ killall apache
</screen>
</para>
</sect1>
<sect1 id="length">
<title>length</title>
<para>
Usage: length STRING
</para>
<para>
Print the length of STRING.
</para>
<para>
Example:
</para>
<para>
<screen>
$ length "Hello"
5
</screen>
</para>
</sect1>
<sect1 id="ln">
<title>ln</title>
<para>
Usage: ln [OPTION]... TARGET FILE|DIRECTORY
</para>
<para>
Create a link named FILE or DIRECTORY to the specified
TARGET. You may use '--' to indicate that all following
arguments are non-options.
</para>
<para>
Options:
</para>
<para>
<screen>
-s Make symbolic link instead of hard link
-f Remove existing destination file
</screen>
</para>
<para>
Example:
</para>
<para>
<screen>
$ ln -s BusyBox /tmp/ls
$ ls -l /tmp/ls
lrwxrwxrwx 1 root root 7 Apr 12 18:39 ls -&gt; BusyBox*
</screen>
</para>
</sect1>
<sect1 id="loadacm">
<title>loadacm</title>
<para>
Usage: loadacm
</para>
<para>
Load an acm from stdin.
</para>
<para>
Example:
</para>
<para>
<screen>
$ loadacm &lt; /etc/i18n/acmname
</screen>
</para>
</sect1>
<sect1 id="loadfont">
<title>loadfont</title>
<para>
Usage: loadfont
</para>
<para>
Load a console font from stdin.
</para>
<para>
Example:
</para>
<para>
<screen>
$ loadfont &lt; /etc/i18n/fontname
</screen>
</para>
</sect1>
<sect1 id="loadkmap">
<title>loadkmap</title>
<para>
Usage: loadkmap
</para>
<para>
Load a binary keyboard translation table from stdin.
</para>
<para>
Example:
</para>
<para>
<screen>
$ loadkmap &lt; /etc/i18n/lang-keymap
</screen>
</para>
</sect1>
<sect1 id="logger">
<title>logger</title>
<para>
Usage: logger [OPTION]... [MESSAGE]
</para>
<para>
Write MESSAGE to the system log. If MESSAGE is '-', log
stdin.
</para>
<para>
Options:
</para>
<para>
<screen>
-s Log to stderr as well as the system log
-t Log using the specified tag (defaults to user name)
-p Enter the message with the specified priority
This may be numerical or a ``facility.level'' pair
</screen>
</para>
<para>
Example:
</para>
<para>
<screen>
$ logger "hello"
</screen>
</para>
</sect1>
<sect1 id="logname">
<title>logname</title>
<para>
Usage: logname
</para>
<para>
Print the name of the current user.
</para>
<para>
Example:
</para>
<para>
<screen>
$ logname
root
</screen>
</para>
</sect1>
<sect1 id="ls">
<title>ls</title>
<para>
Usage: ls [OPTION]... [FILE]...
</para>
<para>
</para>
<para>
Options:
</para>
<para>
<screen>
-a Do not hide entries starting with .
-c With -l: show ctime (the time of last
modification of file status information)
-d List directory entries instead of contents
-e List both full date and full time
-l Use a long listing format
-n List numeric UIDs and GIDs instead of names
-p Append indicator (one of /=@|) to entries
-u With -l: show access time (the time of last
access of the file)
-x List entries by lines instead of by columns
-A Do not list implied . and ..
-C List entries by columns
-F Append indicator (one of */=@|) to entries
-R List subdirectories recursively
</screen>
</para>
<para>
Example:
</para>
<para>
<screen>
</screen>
</para>
</sect1>
<sect1 id="lsmod">
<title>lsmod</title>
<para>
Usage: lsmod
</para>
<para>
List currently loaded kernel modules.
</para>
</sect1>
<sect1 id="makedevs">
<title>makedevs</title>
<para>
Usage: makedevsf NAME TYPE MAJOR MINOR FIRST LAST [s]
</para>
<para>
Create a range of block or character special files.
</para>
<para>
TYPE may be:
</para>
<para>
<screen>
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
</screen>
</para>
<para>
FIRST specifies the number appended to NAME to create
the first device. LAST specifies the number of the last
item that should be created. If 's' is the last
argument, the base device is created as well.
</para>
<para>
Example:
</para>
<para>
<screen>
$ makedevs /dev/ttyS c 4 66 2 63
[creates ttyS2-ttyS63]
$ makedevs /dev/hda b 3 0 0 8 s
[creates hda,hda1-hda8]
</screen>
</para>
</sect1>
<sect1 id="md5sum">
<title>md5sum</title>
<para>
Usage: md5sum [OPTION]... FILE...
</para>
<para>
Print or check MD5 checksums.
</para>
<para>
Options:
</para>
<para>
<screen>
-b Read files in binary mode
-c Check MD5 sums against given list
-t Read files in text mode (default)
-g Read a string
</screen>
</para>
<para>
The following two options are useful only when verifying
checksums:
</para>
<para>
<screen>
-s Don't output anything, status code shows success
-w Warn about improperly formated MD5 checksum lines
</screen>
</para>
<para>
Example:
</para>
<para>
<screen>
$ md5sum busybox
6fd11e98b98a58f64ff3398d7b324003 busybox
$ md5sum -c
6fd11e98b98a58f64ff3398d7b324003 busybox
6fd11e98b98a58f64ff3398d7b324002 busybox
md5sum: MD5 check failed for 'busybox'
^D
</screen>
</para>
</sect1>
<sect1 id="mkdir">
<title>mkdir</title>
<para>
Usage: mkdir [OPTION]... DIRECTORY...
</para>
<para>
Create the DIRECTORY(s), if they do not already exist.
</para>
<para>
Options:
</para>
<para>
<screen>
-m Set permission mode (as in chmod), not rwxrwxrwx - umask
-p No error if directory exists, make parent directories as needed
</screen>
</para>
<para>
Example:
</para>
<para>
<screen>
$ 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
</screen>
</para>
</sect1>
<sect1 id="mkfifo">
<title>mkfifo</title>
<para>
Usage: mkfifo [OPTION] NAME
</para>
<para>
Create a named pipe (identical to 'mknod NAME p').
</para>
<para>
Options:
</para>
<para>
<screen>
-m MODE Create the pipe using the specified mode (default a=rw)
</screen>
</para>
</sect1>
<sect1 id="mkfs.minix">
<title>mkfs.minix</title>
<para>
Usage: mkfs.minix [OPTION]... NAME [BLOCKS]
</para>
<para>
Make a MINIX filesystem.
</para>
<para>
Options:
</para>
<para>
<screen>
-c Check the device for bad blocks
-n [14|30] Specify the maximum length of filenames
-i Specify the number of inodes for the filesystem
-l FILENAME Read the bad blocks list from FILENAME
-v Make a Minix version 2 filesystem
</screen>
</para>
</sect1>
<sect1 id="mknod">
<title>mknod</title>
<para>
Usage: mknod [OPTION]... NAME TYPE MAJOR MINOR
</para>
<para>
Create a special file (block, character, or pipe).
</para>
<para>
Options:
</para>
<para>
<screen>
-m Create the special file using the specified mode (default a=rw)
</screen>
</para>
<para>
TYPE may be:
</para>
<para>
<screen>
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
</screen>
</para>
<para>
Example:
</para>
<para>
<screen>
$ mknod /dev/fd0 b 2 0
$ mknod -m 644 /tmp/pipe p
</screen>
</para>
</sect1>
<sect1 id="mkswap">
<title>mkswap</title>
<para>
Usage: mkswap [OPTION]... DEVICE [BLOCKS]
</para>
<para>
Prepare a disk partition to be used as a swap partition.
</para>
<para>
Options:
</para>
<para>
<screen>
-c Check for read-ability.
-v0 Make version 0 swap [max 128 Megs].
-v1 Make version 1 swap [big!] (default for kernels &gt; 2.1.117).
BLOCKS Number of block to use (default is entire partition).
</screen>
</para>
</sect1>
<sect1 id="mktemp">
<title>mktemp</title>
<para>
Usage: mktemp TEMPLATE
</para>
<para>
Creates a temporary file with its name based on
TEMPLATE. TEMPLATE is any name with six `Xs' (i.e.
/tmp/temp.XXXXXX).
</para>
<para>
Example:
</para>
<para>
<screen>
$ mktemp /tmp/temp.XXXXXX
/tmp/temp.mWiLjM
$ ls -la /tmp/temp.mWiLjM
-rw------- 1 andersen andersen 0 Apr 25 17:10 /tmp/temp.mWiLjM
</screen>
</para>
</sect1>
<sect1 id="more">
<title>more</title>
<para>
Usage: more [FILE]...
</para>
<para>
Page through text one screenful at a time.
</para>
<para>
Example:
</para>
<para>
<screen>
$ dmesg | more
</screen>
</para>
</sect1>
<sect1 id="mount">
<title>mount</title>
<para>
Usage: mount [OPTION]...
</para>
<para>
<screen>
or: mount [OPTION]... DEVICE DIRECTORY
</screen>
</para>
<para>
Mount filesystems.
</para>
<para>
Options:
</para>
<para>
<screen>
-a Mount all filesystems in /etc/fstab
-o One of the many filesystem options listed below
-r Mount the filesystem read-only
-t TYPE Specify the filesystem type
-w Mount the filesystem read-write
</screen>
</para>
<para>
Options for use with the -o flag:
</para>
<para>
<screen>
async/sync Writes are asynchronous / synchronous
atime/noatime Enable / disable updates to inode access times
dev/nodev Allow / disallow use of special device files
exec/noexec Allow / disallow use of executable files
loop Mount a file via loop device
suid/nosuid Allow / disallow set-user-id-root programs
remount Remount a currently mounted filesystem
ro/rw Mount filesystem read-only / read-write
</screen>
</para>
<para>
There are even more flags that are filesystem specific.
You'll have to see the written documentation for those.
</para>
<para>
Example:
</para>
<para>
<screen>
$ 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
</screen>
</para>
</sect1>
<sect1 id="mt">
<title>mt</title>
<para>
Usage: mt [OPTION] OPCODE VALUE
</para>
<para>
Control magnetic tape drive operation.
</para>
<para>
Options:
</para>
<para>
<screen>
-f DEVICE Control DEVICE
</screen>
</para>
</sect1>
<sect1 id="mv">
<title>mv</title>
<para>
Usage: mv SOURCE DEST
</para>
<para>
<screen>
or: mv SOURCE... DIRECTORY
</screen>
</para>
<para>
Rename SOURCE to DEST, or move SOURCE(s) to DIRECTORY.
</para>
<para>
Example:
</para>
<para>
<screen>
$ mv /tmp/foo /bin/bar
</screen>
</para>
</sect1>
<sect1 id="nc">
<title>nc</title>
<para>
Usage: nc HOST PORT
</para>
<para>
Open a pipe to HOST:PORT.
</para>
<para>
Example:
</para>
<para>
<screen>
$ 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
</screen>
</para>
</sect1>
<sect1 id="nslookup">
<title>nslookup</title>
<para>
Usage: nslookup [HOST]
</para>
<para>
Query the nameserver for the IP address of the given
HOST.
</para>
<para>
Example:
</para>
<para>
<screen>
$ nslookup localhost
Server: default
Address: default
Name: debian
Address: 127.0.0.1
</screen>
</para>
</sect1>
<sect1 id="ping">
<title>ping</title>
<para>
Usage: ping [OPTION]... HOST
</para>
<para>
Send ICMP ECHO_REQUEST packets to HOST.
</para>
<para>
Options:
</para>
<para>
<screen>
-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
</screen>
</para>
<para>
Example:
</para>
<para>
<screen>
$ 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
</screen>
</para>
</sect1>
<sect1 id="poweroff">
<title>poweroff</title>
<para>
Usage: poweroff
</para>
<para>
Shut down the system, and request that the kernel turn
off power upon halting.
</para>
</sect1>
<sect1 id="printf">
<title>printf</title>
<para>
Usage: printf FORMAT [ARGUMENT]...
</para>
<para>
Format and print the given data in a manner similar to
the C printf command.
</para>
<para>
Example:
</para>
<para>
<screen>
$ printf "Val=%d\n" 5
Val=5
</screen>
</para>
</sect1>
<sect1 id="ps">
<title>ps</title>
<para>
Usage: ps
</para>
<para>
Report process status. This version of ps accepts no
options.
</para>
<para>
Options:
</para>
<para>
<screen>
</screen>
</para>
<para>
Example:
</para>
<para>
<screen>
$ 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
</screen>
</para>
</sect1>
<sect1 id="pwd">
<title>pwd</title>
<para>
Usage: pwd
</para>
<para>
Print the full filename of the current working
directory.
</para>
<para>
Example:
</para>
<para>
<screen>
$ pwd
/root
</screen>
</para>
</sect1>
<sect1 id="reboot">
<title>reboot</title>
<para>
Usage: reboot
</para>
<para>
Reboot the system.
</para>
</sect1>
<sect1 id="rm">
<title>rm</title>
<para>
Usage: rm [OPTION]... FILE...
</para>
<para>
Remove (unlink) the FILE(s). You may use '--' to
indicate that all following arguments are non-options.
</para>
<para>
Options:
</para>
<para>
<screen>
-f Remove existing destinations, never prompt
-r or -R Remove the contents of directories recursively
</screen>
</para>
<para>
Example:
</para>
<para>
<screen>
$ rm -rf /tmp/foo
</screen>
</para>
</sect1>
<sect1 id="rmdir">
<title>rmdir</title>
<para>
Usage: rmdir DIRECTORY...
</para>
<para>
Remove DIRECTORY(s) if they are empty.
</para>
<para>
Example:
</para>
<para>
<screen>
$ rmdir /tmp/foo
</screen>
</para>
</sect1>
<sect1 id="rmmod">
<title>rmmod</title>
<para>
Usage: rmmod [OPTION]... [MODULE]...
</para>
<para>
Unload MODULE(s) from the kernel.
</para>
<para>
Options:
</para>
<para>
<screen>
-a Try to remove all unused kernel modules
</screen>
</para>
<para>
Example:
</para>
<para>
<screen>
$ rmmod tulip
</screen>
</para>
</sect1>
<sect1 id="sed">
<title>sed</title>
<para>
Usage: sed [OPTION]... SCRIPT [FILE]...
</para>
<para>
Allowed sed scripts come in the following form:
</para>
<para>
<screen>
ADDR [!] COMMAND
</screen>
</para>
<para>
ADDR can be:
</para>
<para>
<screen>
NUMBER Match specified line number
$ Match last line
/REGEXP/ Match specified regexp
</screen>
</para>
<para>
! inverts the meaning of the match
</para>
<para>
COMMAND can be:
</para>
<para>
<screen>
s/regexp/replacement/[igp]
which attempt to match regexp against the pattern space
and if successful replaces the matched portion with replacement.
aTEXT
which appends TEXT after the pattern space
</screen>
</para>
<para>
This version of sed matches full regular expressions.
</para>
<para>
Options:
</para>
<para>
<screen>
-e Add the script to the commands to be executed
-n Suppress automatic printing of pattern space
</screen>
</para>
<para>
Example:
</para>
<para>
<screen>
$ echo "foo" | sed -e 's/f[a-zA-Z]o/bar/g'
bar
</screen>
</para>
</sect1>
<sect1 id="setkeycodes">
<title>setkeycodes</title>
<para>
Usage: setkeycodes SCANCODE KEYCODE ...
</para>
<para>
Set entries into the kernel's scancode-to-keycode map,
allowing unusual keyboards to generate usable keycodes.
</para>
<para>
SCANCODE may be either xx or e0xx (hexadecimal), and
KEYCODE is given in decimal.
</para>
<para>
Example:
</para>
<para>
<screen>
$ setkeycodes e030 127
</screen>
</para>
</sect1>
<sect1 id="sh">
<title>sh</title>
<para>
Usage: sh
</para>
<para>
lash -- the BusyBox LAme SHell (command interpreter)
</para>
<para>
This command does not yet have proper documentation.
</para>
<para>
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 (#!/bin/sh), 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.
</para>
</sect1>
<sect1 id="sleep">
<title>sleep</title>
<para>
Usage: sleep N
</para>
<para>
Pause for N seconds.
</para>
<para>
Example:
</para>
<para>
<screen>
$ sleep 2
[2 second delay results]
</screen>
</para>
</sect1>
<sect1 id="sort">
<title>sort</title>
<para>
Usage: sort [OPTION]... [FILE]...
</para>
<para>
Sort lines of text in FILE(s).
</para>
<para>
Options:
</para>
<para>
<screen>
-n Compare numerically
-r Reverse after sorting
</screen>
</para>
<para>
Example:
</para>
<para>
<screen>
$ echo -e "e\nf\nb\nd\nc\na" | sort
a
b
c
d
e
f
</screen>
</para>
</sect1>
<sect1 id="swapoff">
<title>swapoff</title>
<para>
Usage: swapoff [OPTION] [DEVICE]
</para>
<para>
Stop swapping virtual memory pages on DEVICE.
</para>
<para>
Options:
</para>
<para>
<screen>
-a Stop swapping on all swap devices
</screen>
</para>
</sect1>
<sect1 id="swapon">
<title>swapon</title>
<para>
Usage: swapon [OPTION] [DEVICE]
</para>
<para>
Start swapping virtual memory pages on the given device.
</para>
<para>
Options:
</para>
<para>
<screen>
-a Start swapping on all swap devices
</screen>
</para>
</sect1>
<sect1 id="sync">
<title>sync</title>
<para>
Usage: sync
</para>
<para>
Write all buffered filesystem blocks to disk.
</para>
</sect1>
<sect1 id="syslogd">
<title>syslogd</title>
<para>
Usage: syslogd [OPTION]...
</para>
<para>
Linux system and kernel (provides klogd) logging
utility. Note that this version of syslogd/klogd ignores
/etc/syslog.conf.
</para>
<para>
Options:
</para>
<para>
<screen>
-m NUM Interval between MARK lines (default=20min, 0=off)
-n Run as a foreground process
-K Do not start up the klogd process
-O FILE Use an alternate log file (default=/var/log/messages)
</screen>
</para>
<para>
Example:
</para>
<para>
<screen>
</screen>
</para>
</sect1>
<sect1 id="tail">
<title>tail</title>
<para>
Usage: tail [OPTION] [FILE]...
</para>
<para>
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 stdin.
</para>
<para>
Options:
</para>
<para>
<screen>
-n NUM Print last NUM lines instead of last 10
-f Output data as the file grows. This version
of 'tail -f' supports only one file at a time.
</screen>
</para>
<para>
Example:
</para>
<para>
<screen>
$ tail -n 1 /etc/resolv.conf
nameserver 10.0.0.1
</screen>
</para>
</sect1>
<sect1 id="tar">
<title>tar</title>
<para>
Usage: tar [MODE] [OPTION] [FILE]...
</para>
<para>
</para>
<para>
MODE may be chosen from
</para>
<para>
<screen>
c Create
x Extract
t List
</screen>
</para>
<para>
Options:
</para>
<para>
<screen>
f FILE Use FILE for tarfile (or stdin if '-')
O Extract to stdout
--exclude FILE Exclude FILE
v List files processed
</screen>
</para>
<para>
Example:
</para>
<para>
<screen>
$ zcat /tmp/tarball.tar.gz | tar -xf -
$ tar -cf /tmp/tarball.tar /usr/local
</screen>
</para>
</sect1>
<sect1 id="tee">
<title>tee</title>
<para>
Usage: tee [OPTION]... [FILE]...
</para>
<para>
Copy stdin to FILE(s), and also to stdout.
</para>
<para>
Options:
</para>
<para>
<screen>
-a Append to the given FILEs, do not overwrite
</screen>
</para>
<para>
Example:
</para>
<para>
<screen>
$ echo "Hello" | tee /tmp/foo
Hello
$ cat /tmp/foo
Hello
</screen>
</para>
</sect1>
<sect1 id="telnet">
<title>telnet</title>
<para>
Usage: telnet HOST [PORT]
</para>
<para>
Establish interactive communication with another
computer over a network using the TELNET protocol.
</para>
</sect1>
<sect1 id="test">
<title>test, [</title>
<para>
Usage: test EXPRESSION
</para>
<para>
<screen>
or: [ EXPRESSION ]
<para>
Check file types and compare values returning an exit
code determined by the value of EXPRESSION.
</para>
<para>
Example:
</para>
<para>
<screen>
$ test 1 -eq 2
$ echo $?
1
$ test 1 -eq 1
$ echo $?
0
$ [ -d /etc ]
$ echo $?
0
$ [ -d /junk ]
$ echo $?
1
</screen>
</para>
</sect1>
<sect1 id="touch">
<title>touch</title>
<para>
Usage: touch [OPTION]... FILE...
</para>
<para>
Update the last-modified date on (or create) FILE(s).
</para>
<para>
Options:
</para>
<para>
<screen>
-c Do not create files
</screen>
</para>
<para>
Example:
</para>
<para>
<screen>
$ ls -l /tmp/foo
/bin/ls: /tmp/foo: No such file or directory
$ touch /tmp/foo
$ ls -l /tmp/foo
-rw-rw-r-- 1 andersen andersen 0 Apr 15 01:11 /tmp/foo
</screen>
</para>
</sect1>
<sect1 id="tr">
<title>tr</title>
<para>
Usage: tr [OPTION]... STRING1 [STRING2]
</para>
<para>
Translate, squeeze, and/or delete characters from stdin,
writing to stdout.
</para>
<para>
Options:
</para>
<para>
<screen>
-c Take complement of STRING1
-d Delete input characters coded STRING1
-s Squeeze multiple output characters of STRING2 into one character
</screen>
</para>
<para>
Example:
</para>
<para>
<screen>
$ echo "gdkkn vnqkc" | tr [a-y] [b-z]
hello world
</screen>
</para>
</sect1>
<sect1 id="true">
<title>true</title>
<para>
Usage: true
</para>
<para>
Return an exit code of TRUE (1).
</para>
<para>
Example:
</para>
<para>
<screen>
$ true
$ echo $?
0
</screen>
</para>
</sect1>
<sect1 id="tty">
<title>tty</title>
<para>
Usage: tty
</para>
<para>
Print the file name of the terminal connected to stdin.
</para>
<para>
Options:
</para>
<para>
<screen>
-s Print nothing, only return an exit status
</screen>
</para>
<para>
Example:
</para>
<para>
<screen>
$ tty
/dev/tty2
</screen>
</para>
</sect1>
<sect1 id="umount">
<title>umount</title>
<para>
Usage: umount [OPTION]... DEVICE|DIRECTORY
</para>
<para>
</para>
<para>
Options:
</para>
<para>
<screen>
-a Unmount all file systems
-r Try to remount devices as read-only if mount is busy
-f Force filesystem umount (i.e. unreachable NFS server)
-l Do not free loop device (if a loop device has been used)
</screen>
</para>
<para>
Example:
</para>
<para>
<screen>
$ umount /dev/hdc1
</screen>
</para>
</sect1>
<sect1 id="uname">
<title>uname</title>
<para>
Usage: uname [OPTION]...
</para>
<para>
Print certain system information. With no OPTION, same
as -s.
</para>
<para>
Options:
</para>
<para>
<screen>
-a Print all information
-m Print the machine (hardware) type
-n Print the machine's network node hostname
-r Print the operating system release
-s Print the operating system name
-p Print the host processor type
-v Print the operating system version
</screen>
</para>
<para>
Example:
</para>
<para>
<screen>
$ uname -a
Linux debian 2.2.15pre13 #5 Tue Mar 14 16:03:50 MST 2000 i686 unknown
</screen>
</para>
</sect1>
<sect1 id="uniq">
<title>uniq</title>
<para>
Usage: uniq [INPUT [OUTPUT]]
</para>
<para>
Discard all but one of successive identical lines from
INPUT (or stdin), writing to OUTPUT (or stdout).
</para>
<para>
Example:
</para>
<para>
<screen>
$ echo -e "a\na\nb\nc\nc\na" | sort | uniq
a
b
c
</screen>
</para>
</sect1>
<sect1 id="update">
<title>update</title>
<para>
Usage: update [OPTION]...
</para>
<para>
Periodically flush filesystem buffers.
</para>
<para>
Options:
</para>
<para>
<screen>
-S Force use of sync(2) instead of flushing
-s SECS Call sync this often (default 30)
-f SECS Flush some buffers this often (default 5)
</screen>
</para>
</sect1>
<sect1 id="uptime">
<title>uptime</title>
<para>
Usage: uptime
</para>
<para>
Display how long the system has been running since boot.
</para>
<para>
Example:
</para>
<para>
<screen>
$ uptime
1:55pm up 2:30, load average: 0.09, 0.04, 0.00
</screen>
</para>
</sect1>
<sect1 id="usleep">
<title>usleep</title>
<para>
Usage: usleep N
</para>
<para>
Pause for N microseconds.
</para>
<para>
Example:
</para>
<para>
<screen>
$ usleep 1000000
[pauses for 1 second]
</screen>
</para>
</sect1>
<sect1 id="uudecode">
<title>uudecode</title>
<para>
Usage: uudecode [OPTION] [FILE]
</para>
<para>
Uudecode a uuencoded file.
</para>
<para>
Options:
</para>
<para>
<screen>
-o FILE Direct output to FILE
</screen>
</para>
<para>
Example:
</para>
<para>
<screen>
$ uudecode -o busybox busybox.uu
$ ls -l busybox
-rwxr-xr-x 1 ams ams 245264 Jun 7 21:35 busybox
</screen>
</para>
</sect1>
<sect1 id="uuencode">
<title>uuencode</title>
<para>
Usage: uuencode [OPTION] [INFILE] OUTFILE
</para>
<para>
Uuencode a file.
</para>
<para>
Options:
</para>
<para>
<screen>
-m Use base64 encoding as of RFC1521
</screen>
</para>
<para>
Example:
</para>
<para>
<screen>
$ uuencode busybox busybox
begin 755 busybox
M?T5,1@$!`0````````````(``P`!````L+@$"#0```!0N@,``````#0`(``&amp;
.....
$ uudecode busybox busybox &gt; busybox.uu
$
</screen>
</para>
</sect1>
<sect1 id="wc">
<title>wc</title>
<para>
Usage: wc [OPTION]... [FILE]...
</para>
<para>
Print line, word, and byte counts for each FILE, and a
total line if more than one FILE is specified. With no
FILE, read stdin.
</para>
<para>
Options:
</para>
<para>
<screen>
-c Print the byte counts
-l Print the newline counts
-L Print the length of the longest line
-w Print the word counts
</screen>
</para>
<para>
Example:
</para>
<para>
<screen>
$ wc /etc/passwd
31 46 1365 /etc/passwd
</screen>
</para>
</sect1>
<sect1 id="which">
<title>which</title>
<para>
Usage: which [COMMAND]...
</para>
<para>
Locate COMMAND(s).
</para>
<para>
Example:
</para>
<para>
<screen>
$ which login
/bin/login
</screen>
</para>
</sect1>
<sect1 id="whoami">
<title>whoami</title>
<para>
Usage: whoami
</para>
<para>
Print the user name associated with the current
effective user id.
</para>
<para>
Example:
</para>
<para>
<screen>
$ whoami
andersen
</screen>
</para>
</sect1>
<sect1 id="yes">
<title>yes</title>
<para>
Usage: yes [STRING]...
</para>
<para>
Repeatedly output a line with all specified STRING(s),
or `y'.
</para>
</sect1>
<sect1 id="zcat">
<title>zcat</title>
<para>
Usage: zcat [OPTION]... FILE
</para>
<para>
Uncompress FILE (or stdin if FILE is '-') to stdout.
</para>
<para>
Options:
</para>
<para>
<screen>
-t Test compressed file integrity
</screen>
</para>
<para>
Example:
</para>
<para>
<screen>
</screen>
</para>
</sect1>
</chapter>
<chapter id="LIBC-NSS">
<title>LIBC NSS</title>
<para>
GNU Libc 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. BusyBox has made it Policy that it will never use
NSS, and will never use libc calls that make use of NSS. This
allows you to run an embedded system without the need for
installing an /etc/nsswitch.conf file and without /lib/libnss_*
libraries installed.
</para>
<para>
If you are using a system that is using a remote LDAP server for
authentication via GNU libc NSS, and you want to use BusyBox,
then you will need to adjust the BusyBox source. Chances are
though, that if you have enough space to install of that stuff
on your system, then you probably want the full GNU utilities.
</para>
</chapter>
<chapter id="SEE-ALSO">
<title>SEE ALSO</title>
<para>
<literal>textutils(1),</literal>
<literal>shellutils(1),</literal>
etc...
</para>
</chapter>
<chapter id="MAINTAINER">
<title>MAINTAINER</title>
<para>
Erik Andersen &lt;andersee@debian.org&gt; &lt;andersen@lineo.com&gt;
</para>
</chapter>
<chapter id="AUTHORS">
<title>AUTHORS</title>
<para>
The following people have contributed code to BusyBox whether
they know it or not.
</para>
<para>
Erik Andersen &lt;andersee@debian.org&gt;
</para>
<para>
John Beppu &lt;beppu@lineo.com&gt;
</para>
<para>
Brian Candler &lt;B.Candler@pobox.com&gt;
</para>
<para>
Randolph Chung &lt;tausq@debian.org&gt;
</para>
<para>
Dave Cinege &lt;dcinege@psychosis.com&gt;
</para>
<para>
Karl M. Hegbloom &lt;karlheg@debian.org&gt;
</para>
<para>
John Lombardo &lt;john@deltanet.com&gt;
</para>
<para>
Glenn McGrath &lt;bug1@netconnect.com.au&gt;
</para>
<para>
Bruce Perens &lt;bruce@perens.com&gt;
</para>
<para>
Pavel Roskin &lt;proski@gnu.org&gt;
</para>
<para>
Linus Torvalds &lt;torvalds@transmeta.com&gt;
</para>
<para>
Charles P. Wright &lt;cpwright@villagenet.com&gt;
</para>
<para>
Enrique Zanardi &lt;ezanardi@ull.es&gt;
</para>
</chapter>
</book> <!-- End of the book -->