adduser - used by root to add user to system
apropos - display command names based on keyword search
ar - create, modify and extract from archives
arch - print machine architecture type
as - the portable GNU assembler
awk - searches for and process patterns in a file
bash - Bourne again shell.
bc - a language (compiler) similar to C, with unlimited precision arithmetic
bg PID - send process with pid ``PID'' to the background. This is the same as executing [Ctrl]z while interacting with the running process. This is a shell builtin.
bison - parser generator similar to yacc
bunzip2 - used to uncompress files compressed with bzip2
bzip2 - compresses with algorithm different from gzip
bzless - view bzipped files
c++ - invokes GNU C and C++ compiler
cal - displays a 12-month calendar for the given year or a one-month calendar of the given month
cat - combine, copy standard input to standard output. Used to join or display files.
cd - change working directory. This is a shell builtin in bash, tcsh and zsh.
cfdisk - similar to fdisk, but menu-driven
chgrp - changes group associated with file. Can be used to change the group associated with subdirectories and files of a directory.
chmod - set permissions (modes) of files or directories.
chown - changes ownership of a file. Can be used recursively.
chsh - change default shell
clear - clear screen command
cp - copies on or more files.
cpio - direct copy of files to an output device.
find - find files with many filters possible.
cpp - GNU C-compatible compiler preprocessor
crontab - schedules command to run at regularly specified time
csh - run C shell
csplit - separate files into sections. See also split.
cut - selects characters or TAB-separated fields from lines of input and writes them to standard output
date - displays or sets date and time
dd - direct copy of file from one device to another.
diff - displays differences between two files
diff3 - compares three files and reports on differences
dir - a variation of the GNU ls command that defaults to printing file names in columns
dmesg - displays messages from /var/log relative to the most recent boot
du - displays information on disk usage. The command
dumpkeys - print information about the keyboard driver's translation tables to standard output
emacs - screen oriented text editor
env - desplay the current environment or set a variable equal to a new value
eval - scans and evaluates the command line. See dircolors command. This is a shell builtin.
exec - system call which creates a subshell to execute a binary or a script. This is a shell builtin.
execve - a variation of the exec command.
exit - exit a shell. This is a shell builtin.
expand - convert tabs in files to spaces and write to standard output
expect - a program that can react automaticallu based the output of another program (written in tcl).
export - place the value of a variable in the calling environment (makes it global). This is a shell builtin.
expr - utility evaluates an expression and displays the result
false - null command that returns an unsuccessful exit status
fc - views, edits, and executes commands for the history list. This is a shell builtin.
fg PID - bring a background or stopped process with pid ``PID'' to the foreground.
file - displays classification of a file or files according to the type of data they contain
find - find files according to a large variety of search criteria.
fmt - simple text formatting utility. Tries to make all nonblank lines nearly the same length.
fold - break lines of specified files so they are no wider than a specified lengths
free - gives used and free memory on system along with other useful information
fsck - file system check and repair
g++ - C++ compiler
gawk - GNU awk, mostly for processing delimited text files
gcc - invoke C, C++ compiler
getopts - parses arguments to a shell script. This is a shell builtin.
grep - used to find a string within a file. The -i option returns matches without regard to case. The -n option means that each line of output is preceded
groupadd - create a new group on the system
groups - shows which groups you are in
grub-install - install the grub bootloader on a disk/partition
gunzip - used to uncompress files compressed with gzip
gzexe - compresses executables
gzip - used to compress or decompress files
halt - shut down system as root, without reboot, immediately
hash - remembers the location of commands in the search path. This is a shell builtin.
head - displays first part of a file
history - command for viewing and manipulating the shell command history list
hostname - used to get or set hostname. Typically, the host name is stored in the file /etc/HOSTNAME.
hwclock - used to query and set the hardware clock
id - display userid and groupid
jobs - displays list of current jobs in the background. This is a shell builtin.
kill - sends a signal to (especially to terminate) a job or process. This is a shell builtin in bash, tcsh and zsh.
killall - kill processes by name. Kill all processes which are instances of the speciffied program. Also used to send signals to processes or restart them.
last - generate a listing of user logins
lastlog - prints the last login times of all users
latex - compile a LATEX file
ldconfig - creates the necessary links and cache (for use by the run-time linker, ld.so) to the most recent shared libraries found in the directories specified on the command line, in the file /etc/ld.so.conf, and in the trusted directories (/usr/lib and /lib). Ldconfig checks the header and file names of the libraries it encounters when determining which versions should have their links updated. Ldconfig ignores symbolic links when scanning for libraries.
ldd - list the shared libraries on which a given executable depends, and where they are located
less - Linux alternative to ``more'' command. Displays text files, one screenful at a time. When less pauses, there is a large number of available commands to tell it what to do next. One can scroll both forwards and backwards.
let - evaluates a numeric expression. This is a shell builtin.
logname - consult /etc/utmp for user's login name
logout - execute logout as individual user and bring up login: prompt
look - look for strings in files
ls - list directory contents.
lsattr - list attributes of files in ext2 file system
lsmod - used (by root) to show kernel modules currently loaded
lspci - utility to display information on pci buses and hardware devices attached to them.
lspnp - utility to display information about pnp devices. Part of the pcmcia or kernel-pcmcia package, depending on the distribution.
mail - sends or reads electronic mail (use bsd-mailx instead)
make - keeps a set of programs current. This is a utility that helps when developing a set of programs. It works by executing a script called makefile, Makefile or GNUmakefile in the working directory. It is very often used in combination with configure when compiling and installing noncompiled software packages.
man - displays information from online Unix reference manual
manpath - attempt to determine path to manual pages
mkdir - create a directory
mkfs - create a file system (format)
mkswap - creates a Linux swap space on the specified hard disk parition (root privileges needed)
more - list file contents, stopping after each full screen
mount - mount device in the filesystem directory tree
mount -a - mount all filesystems according to the specifications in /etc/fstab
mv - moves (renames) files
newaliases - rebuilds the /etc/aliases database used by local MTA. Must be rerun every time /etc/aliases is modified for the changes to take effect.
newgrp - similar to login. Changes user's identification
nice program_name - sets the priority of the program ``program_name''.
nm - lists the symbols from object files objfile. If no object files are given as arguments, nm assumes `a.out'.
nohup - runs a command that keeps running after logout. The command is in principle immune to hangups, and must have output to a non tty. According to Linux in a Nutshell, this is necessary only in the Bourne shell, since modern shells preserve background processes by default.
od - dumps contents of a file (output in octal by default)
passwd - change login password
paste - joins corresponding lines from files
patch - updates source code. Attempts to update a file from a file of change information, or pathces, created by diff.
pathchk - determine validity and portability of filenames
ping - check if Internet computer is responding. Can also measure the time it takes the queried computer to respond.
pr - paginates files for printing
printenv - display list of environment variables
ps - displays status of processes.
pstree - display processes in the form of a tree structure.
pushd - pushes the argument onto the top of the directory stack and uses cd to change to that directory. This is a shell builtin.
pwd - print absolute path of working directory. This is a shell builtin.
python - interpreted, interactive, object-oriented programming language
read - reads line from standard input. This is a shell builtin.
readonly - declares a variable to be read only. This is a shell builtin.
reboot - reboots the system. equivalent to shutdown -r now
renice program_name - resets the priority of process ``program_name''.
reset - used to reset the screen characteristics. This is useful if the screen gets messed up from, for example, trying to display a binary file in an xterm.
return - exits from a function. This is a shell builtin.
rm - remove files or directories.
rmdir - remove empty directories
rmmod - used to remove modular device drivers
sed - edits a file (not interactively). Also a tool for processing text files.
set - set or display value of shell variables.
sh - standard UNIX shell.
shift - promotes each command-line argument. This is a shell builtin.
showmount - show information about an nfs server
shutdown - reboot or shut down system as root
sleep - creates process that sleeps for specified interval
sort - sorts and/or merge files
split - split file into specified number of segments
ssh - secure shell client to connect to remote servers running sshd
stty - sets or displays operating options for terminal
su - log in as another user, including root
sudo - allows individual users to have root permission to perform specified tasks
swapoff - disables swap disk
swapon - enables swap disk
sync - writes memory buffers to physical devices
systat - query host for system information
tac - print file in reverse
tail - displays the last part of a file
tar - file compression and archiving utility.
tcl - scripting language
tcsh - extended version of the C shell
tee - copy standard input to standard output and one or more files
test - evaluates an expression or compares arguments. This is a shell builtin in bash, tcsh and zsh.
tftp - user interface to TFTP protocol
top - dynamically displays process status
touch - update access and modification times of a file. If the file does not exist on disk, an empty file is created.
tr - translation utility that can be used, for example, to replace specified characters in a text file
trap - traps a signal. This is a shell builtin.
true - null command that returns a successful exit status
tset - initializes terminal
tty - shows special file that represents your terminal. Displays the terminal pathname.
type - displays how each argument would be interpreted as a command. This is a shell builtin.
typeset - declares attributes for a variaable (same as declare). This is a shell builtin.
ul - translate underscores to underlining
umask - establishes the file-creation permissions mask.
umount - finish writing to the device and remove it from the active filesystem. The command umount -a will (re)mount all file systems listed in /etc/fstab.
uname - displays information about the system.
uniq - displays lines of a file that are unique
unset - removes a variable or function. This is a shell builtin.
unzip - uncompress files compressed with the zip utility, compatible with DOS PKzip
uptime - shows the time, how long the system has been up, the number of users, and average load.
useradd - same as adduser
userdel - remove an account (as root). The user's home directory and undelivered mail must be dealt with separately.
users - prints list of users on the system
vim - improved vi editor
w - display info about userids and active processes
wait - waits for a background process to terminate. This is a shell builtin.
wc - displays number of lines, characters and words in a file
whatis - display one-line summary of specified command
whereis - use to find utilities in standard locations
which - used to find utilities in search path. Will return the absolute directory path of the named utility program.
who - display information about currently logged in userids
whoami - display information about userid that is currently logged in
wish - front end to tk, an X window extension of tcl
write - send messages to another local user
xinit - start X Window. The command startx is a front end to xinit in Linux, including Slackware.
zcat - read one or more files that have been compressed with gzip or compress and write to standard output
zcmp - read compressed files and pass them to cmp
zdiff - read compressed files and pass them to diff
zgrep - read compressed files and pass them to grep
zip - zip utility compatible with DOS PKzip
zless - view zipped files
zmore - print contents of compressed files one screen at a time
znew - uncompress Z files and recompress in .gz format