Linux

= Learn More about linux ? =
 * http://en.wikipedia.org/wiki/Linux
 * http://en.wikipedia.org/wiki/Comparison_of_Windows_and_Linux
 * http://en.wikipedia.org/wiki/Linux_distribution
 * http://en.wikipedia.org/wiki/Desktop_Linux
 * http://en.wikipedia.org/wiki/Linux_gaming

= An A-Z Index of the Bash command line for Linux =
 * source http://www.ss64.com/bash/

a
alias   Create an alias • apropos Search Help manual pages (man -k) apt-get Search for and install software packages (Debian/Ubuntu) aptitude Search for and install software packages (Debian/Ubuntu) aspell  Spell Checker awk     Find and Replace text, database sort/validate/index

b
basename Strip directory and suffix from filenames bash    GNU Bourne-Again SHell bc      Arbitrary precision calculator language bg      Send to background break   Exit from a loop • builtin Run a shell builtin bzip2   Compress or decompress named file(s)

c
cal     Display a calendar case    Conditionally perform a command cat     Concatenate and print (display) the content of files cd      Change Directory cfdisk  Partition table manipulator for Linux chgrp   Change group ownership chmod   Change access permissions chown   Change file owner and group chroot  Run a command with a different root directory chkconfig System services (runlevel) cksum   Print CRC checksum and byte counts clear   Clear terminal screen cmp     Compare two files comm    Compare two sorted files line by line command Run a command - ignoring shell functions • continue Resume the next iteration of a loop • cp      Copy one or more files to another location cron    Daemon to execute scheduled commands crontab Schedule a command to run at a later time csplit  Split a file into context-determined pieces cut     Divide a file into several parts

d
date    Display or change the date & time dc      Desk Calculator dd      Convert and copy a file, write disk headers, boot records ddrescue Data recovery tool declare Declare variables and give them attributes • df      Display free disk space diff    Display the differences between two files diff3   Show differences among three files dig     DNS lookup dir     Briefly list directory contents dircolors Colour setup for `ls' dirname Convert a full pathname to just a path dirs    Display list of remembered directories dmesg   Print kernel & driver messages du      Estimate file space usage

e
echo    Display message on screen • egrep   Search file(s) for lines that match an extended expression eject   Eject removable media enable  Enable and disable builtin shell commands • env     Environment variables ethtool Ethernet card settings eval    Evaluate several commands/arguments exec    Execute a command exit    Exit the shell expect  Automate arbitrary applications accessed over a terminal expand  Convert tabs to spaces export  Set an environment variable expr    Evaluate expressions

f
false   Do nothing, unsuccessfully fdformat Low-level format a floppy disk fdisk   Partition table manipulator for Linux fg      Send job to foreground fgrep   Search file(s) for lines that match a fixed string file    Determine file type find    Search for files that meet a desired criteria fmt     Reformat paragraph text fold    Wrap text to fit a specified width. for     Expand words, and execute commands format  Format disks or tapes free    Display memory usage fsck    File system consistency check and repair ftp     File Transfer Protocol function Define Function Macros fuser   Identify/kill the process that is accessing a file

g
gawk    Find and Replace text within file(s) getopts Parse positional parameters grep    Search file(s) for lines that match a given pattern groupadd Add a user security group groupdel Delete a group groupmod Modify a group groups  Print group names a user is in  gzip     Compress or decompress named file(s)

h
hash    Remember the full pathname of a name argument head    Output the first part of file(s) help    Display help for a built-in command • history Command History hostname Print or set system name

i
iconv   Convert the character set of a file id      Print user and group id's  if       Conditionally perform a command ifconfig Configure a network interface ifdown  Stop a network interface ifup    Start a network interface up  import   Capture an X server screen and save the image to file install Copy files and set attributes

j
jobs    List active jobs • join    Join lines on a common field

k
kill    Stop a process from running killall Kill processes by name

l
less    Display output one screen at a time let     Perform arithmetic on shell variables • link    Create a link to a file ln      Create a symbolic link to a file local   Create variables • locate  Find files logname Print current login name logout  Exit a login shell • look    Display lines beginning with a given string lpc     Line printer control program lpr     Off line print lprint  Print a file lprintd Abort a print job lprintq List the print queue lprm    Remove jobs from the print queue ls      List information about file(s) lsof    List open files

m
make    Recompile a group of programs man     Help manual mkdir   Create new folder(s) mkfifo  Make FIFOs (named pipes) mkisofs Create an hybrid ISO9660/JOLIET/HFS filesystem mknod   Make block or character special files more    Display output one screen at a time mount   Mount a file system mtools  Manipulate MS-DOS files mtr     Network diagnostics (traceroute/ping) mv      Move or rename files or directories mmv     Mass Move and rename (files)

n
netstat Networking information nice    Set the priority of a command or job nl      Number lines and write files nohup   Run a command immune to hangups notify-send Send desktop notifications nslookup Query Internet name servers interactively

o
open    Open a file in its default application op      Operator access

p
passwd  Modify a user password paste   Merge lines of files pathchk Check file name portability ping    Test a network connection pkill   Stop processes from running popd    Restore the previous value of the current directory pr      Prepare files for printing printcap Printer capability database printenv Print environment variables printf  Format and print data • ps      Process status pushd   Save and then change the current directory pwd     Print Working Directory

q
quota   Display disk usage and limits quotacheck Scan a file system for disk usage quotactl Set disk quotas

r
ram     ram disk device rcp     Copy files between two machines read    Read a line from standard input • readarray Read from stdin into an array variable • readonly Mark variables/functions as readonly reboot  Reboot the system rename  Rename files renice  Alter priority of running processes remsync Synchronize remote files via email return  Exit a shell function rev     Reverse lines of a file rm      Remove files rmdir   Remove folder(s) rsync   Remote file copy (Synchronize file trees)

s
screen  Multiplex terminal, run remote shells via ssh scp     Secure copy (remote file copy) sdiff   Merge two files interactively sed     Stream Editor select  Accept keyboard input seq     Print numeric sequences set     Manipulate shell variables and functions sftp    Secure File Transfer Program shift   Shift positional parameters shopt   Shell Options shutdown Shutdown or restart linux sleep   Delay for a specified time slocate Find files sort    Sort text files source  Run commands from a file '.' split   Split a file into fixed-size pieces ssh     Secure Shell client (remote login program) strace  Trace system calls and signals su      Substitute user identity sudo    Execute a command as another user sum     Print a checksum for a file suspend Suspend execution of this shell • sync    Synchronize data on disk with memory

t
tail    Output the last part of file tar     Tape ARchiver tee     Redirect output to multiple files test    Evaluate a conditional expression time    Measure Program running time timeout Run a command with a time limit times   User and system times touch   Change file timestamps top     List processes running on the system traceroute Trace Route to Host trap    Run a command when a signal is set(bourne) tr      Translate, squeeze, and/or delete characters true    Do nothing, successfully tsort   Topological sort tty     Print filename of terminal on stdin type    Describe a command •

u
ulimit  Limit user resources • umask   Users file creation mask umount  Unmount a device unalias Remove an alias • uname   Print system information unexpand Convert spaces to tabs uniq    Uniquify files units   Convert units from one scale to another unset   Remove variable or function names unshar  Unpack shell archive scripts until   Execute commands (until error) uptime  Show uptime useradd Create new user account userdel Delete a user account usermod Modify user account users   List users currently logged in  uuencode Encode a binary file uudecode Decode a file created by uuencode

v
v       Verbosely list directory contents (`ls -l -b') vdir    Verbosely list directory contents (`ls -l -b') vi      Text Editor vmstat  Report virtual memory statistics

w
wait    Wait for a process to complete • watch   Execute/display a program periodically wc      Print byte, word, and line counts whereis Search the user's $path, man pages and source files for a program which   Search the user's $path for a program file while   Execute commands who     Print all usernames currently logged in  whoami   Print the current user id and name (`id -un') wget    Retrieve web pages or files via HTTP, HTTPS or FTP write   Send a message to another user

x
xargs   Execute utility, passing constructed argument list(s) xdg-open Open a file or URL in the user's preferred application. yes     Print a string until interrupted

anotations
.       Run a command script in the current shell !!      Run the last command again ###     Comment / Remark : Commands marked • are bash built-ins : Many commands particularly the Core Utils are also available under alternate shells (C shell, Korn shell etc).