1Command adduser |Add a user to the system 2Command addgroup |Add a group to the system 3Command alias |Create an alias 4Command apropos |Search Help manual pages (man -k) 5Command apt-get |Search for and install software packages (Debian/Ubuntu) 6Command aptitude |Search for and install software packages (Debian/Ubuntu) 7Command aspell |Spell Checker 8Command awk |Find and Replace text, database sort/validate/index 9Command basename |Strip directory and suffix from filenames 10Command bash |GNU Bourne-Again SHell 11Command bc |Arbitrary precision calculator language 12Command bg |Send to background 13Command break |Exit from a loop 14Command builtin |Run a shell builtin 15Command bzip2 |Compress or decompress named file(s) 16Command cal |Display a calendar 17Command case |Conditionally perform a command 18Command cat |Display the contents of a file 19Command cd |Change Directory 20Command cfdisk |Partition table manipulator for Linux 21Command chgrp |Change group ownership 22Command chmod |Change access permissions 23Command chown |Change file owner and group 24Command chroot |Run a command with a different root directory 25Command chkconfig |System services (runlevel) 26Command cksum |Print CRC checksum and byte counts 27Command clear |Clear terminal screen 28Command cmp |Compare two files 29Command comm |Compare two sorted files line by line 30Command command |Run a command - ignoring shell functions 31Command continue |Resume the next iteration of a loop 32Command cp |Copy one or more files to another location 33Command cron |Daemon to execute scheduled commands 34Command crontab |Schedule a command to run at a later time 35Command csplit |Split a file into context-determined pieces 36Command cut |Divide a file into several parts 37Command date |Display or change the date & time 38Command dc |Desk Calculator 39Command dd |Convert and copy a file, write disk headers, boot records 40Command ddrescue |Data recovery tool 41Command declare |Declare variables and give them attributes 42Command df |Display free disk space 43Command diff |Display the differences between two files 44Command diff3 |Show differences among three files 45Command dig |DNS lookup 46Command dir |Briefly list directory contents 47Command dircolors |Colour setup for `ls' 48Command dirname |Convert a full pathname to just a path 49Command dirs |Display list of remembered directories 50Command dmesg |Print kernel & driver messages 51Command du |Estimate file space usage 52Command echo |Display message on screen 53Command egrep |Search file(s) for lines that match an extended expression 54Command eject |Eject removable media 55Command enable |Enable and disable builtin shell commands 56Command env |Environment variables 57Command ethtool |Ethernet card settings 58Command eval |Evaluate several commands/arguments 59Command exec |Execute a command 60Command exit |Exit the shell 61Command expect |Automate arbitrary applications accessed over a terminal 62Command expand |Convert tabs to spaces 63Command export |Set an environment variable 64Command expr |Evaluate expressions 65Command false |Do nothing, unsuccessfully 66Command fdformat |Low-level format a floppy disk 67Command fdisk |Partition table manipulator for Linux 68Command fg |Send job to foreground 69Command fgrep |Search file(s) for lines that match a fixed string 70Command file |Determine file type 71Command find |Search for files that meet a desired criteria 72Command fmt |Reformat paragraph text 73Command fold |Wrap text to fit a specified width. 74Command for |Expand words, and execute commands 75Command format |Format disks or tapes 76Command free |Display memory usage 77Command fsck |File system consistency check and repair 78Command ftp |File Transfer Protocol 79Command function |Define Function Macros 80Command fuser |Identify/kill the process that is accessing a file 81Command gawk |Find and Replace text within file(s) 82Command getopts |Parse positional parameters 83Command grep |Search file(s) for lines that match a given pattern 84Command groups |Print group names a user is in 85Command gzip |Compress or decompress named file(s) 86Command hash |Remember the full pathname of a name argument 87Command head |Output the first part of file(s) 88Command help |Display help for a built-in command 89Command history |Command History 90Command hostname |Print or set system name 91Command id |Print user and group id's 92Command if |Conditionally perform a command 93Command ifconfig |Configure a network interface 94Command ifdown |Stop a network interface 95Command ifup |Start a network interface up 96Command import |Capture an X server screen and save the image to file 97Command install |Copy files and set attributes 98Command jobs |List active jobs 99Command join |Join lines on a common field 100Command kill |Stop a process from running 101Command killall |Kill processes by name 102Command less |Display output one screen at a time 103Command let |Perform arithmetic on shell variables 104Command ln |Make links between files 105Command local |Create variables 106Command locate |Find files 107Command logname |Print current login name 108Command logout |Exit a login shell 109Command look |Display lines beginning with a given string 110Command lpc |Line printer control program 111Command lpr |Off line print 112Command lprint |Print a file 113Command lprintd |Abort a print job 114Command lprintq |List the print queue 115Command lprm |Remove jobs from the print queue 116Command ls |List information about file(s) 117Command lsof |List open files 118Command make |Recompile a group of programs 119Command man |Help manual 120Command mkdir |Create new folder(s) 121Command mkfifo |Make FIFOs (named pipes) 122Command mkisofs |Create an hybrid ISO9660/JOLIET/HFS filesystem 123Command mknod |Make block or character special files 124Command more |Display output one screen at a time 125Command mount |Mount a file system 126Command mtools |Manipulate MS-DOS files 127Command mtr |Network diagnostics (traceroute/ping) 128Command mv |Move or rename files or directories 129Command mmv |Mass Move and rename (files) 130Command netstat |Networking information 131Command nice |Set the priority of a command or job 132Command nl |Number lines and write files 133Command nohup |Run a command immune to hangups 134Command notify-send |Send desktop notifications 135Command nslookup |Query Internet name servers interactively 136Command open |Open a file in its default application 137Command op |Operator access 138Command passwd |Modify a user password 139Command paste |Merge lines of files 140Command pathchk |Check file name portability 141Command ping |Test a network connection 142Command pkill |Stop processes from running 143Command popd |Restore the previous value of the current directory 144Command pr |Prepare files for printing 145Command printcap |Printer capability database 146Command printenv |Print environment variables 147Command printf |Format and print data 148Command ps |Process status 149Command pushd |Save and then change the current directory 150Command pwd |Print Working Directory 151Command quota |Display disk usage and limits 152Command quotacheck |Scan a file system for disk usage 153Command quotactl |Set disk quotas 154Command ram |ram disk device 155Command rcp |Copy files between two machines 156Command read |Read a line from standard input 157Command readarray |Read from stdin into an array variable 158Command readonly |Mark variables/functions as readonly 159Command reboot |Reboot the system 160Command rename |Rename files 161Command renice |Alter priority of running processes 162Command remsync |Synchronize remote files via email 163Command return |Exit a shell function 164Command rev |Reverse lines of a file 165Command rm |Remove files 166Command rmdir |Remove folder(s) 167Command rsync |Remote file copy (Synchronize file trees) 168Command screen |Multiplex terminal, run remote shells via ssh 169Command scp |Secure copy (remote file copy) 170Command sdiff |Merge two files interactively 171Command sed |Stream Editor 172Command select |Accept keyboard input 173Command seq |Print numeric sequences 174Command set |Manipulate shell variables and functions 175Command sftp |Secure File Transfer Program 176Command shift |Shift positional parameters 177Command shopt |Shell Options 178Command shutdown |Shutdown or restart linux 179Command sleep |Delay for a specified time 180Command slocate |Find files 181Command sort |Sort text files 182Command source |Run commands from a file `.' 183Command split |Split a file into fixed-size pieces 184Command ssh |Secure Shell client (remote login program) 185Command strace |Trace system calls and signals 186Command su |Substitute user identity 187Command sudo |Execute a command as another user 188Command sum |Print a checksum for a file 189Command suspend |Suspend execution of this shell 190Command symlink |Make a new name for a file 191Command sync |Synchronize data on disk with memory 192Command tail |Output the last part of files 193Command tar |Tape ARchiver 194Command tee |Redirect output to multiple files 195Command test |Evaluate a conditional expression 196Command time |Measure Program running time 197Command times |User and system times 198Command touch |Change file timestamps 199Command top |List processes running on the system 200Command traceroute |Trace Route to Host 201Command trap |Run a command when a signal is set(bourne) 202Command tr |Translate, squeeze, and/or delete characters 203Command true |Do nothing, successfully 204Command tsort |Topological sort 205Command tty |Print filename of terminal on stdin 206Command type |Describe a command 207Command ulimit |Limit user resources 208Command umask |Users file creation mask 209Command umount |Unmount a device 210Command unalias |Remove an alias 211Command uname |Print system information 212Command unexpand |Convert spaces to tabs 213Command uniq |Uniquify files 214Command units |Convert units from one scale to another 215Command unset |Remove variable or function names 216Command unshar |Unpack shell archive scripts 217Command until |Execute commands (until error) 218Command useradd |Create new user account 219Command usermod |Modify user account 220Command users |List users currently logged in 221Command uuencode |Encode a binary file 222Command uudecode |Decode a file created by uuencode 223Command v |Verbosely list directory contents (`ls -l -b') 224Command vdir |Verbosely list directory contents (`ls -l -b') 225Command vi |Text Editor 226Command vmstat |Report virtual memory statistics 227Command watch |Execute/display a program periodically 228Command wc |Print byte, word, and line counts 229Command whereis |Search the user's $path, man pages and source files for a program 230Command which |Search the user's $path for a program file 231Command while |Execute commands 232Command who |Print all usernames currently logged in 233Command whoami |Print the current user id and name (`id -un') 234Command Wget |Retrieve web pages or files via HTTP, HTTPS or FTP 235Command write |Send a message to another user 236Command xargs |Execute utility, passing constructed argument list(s) 237Command xdg-open |Open a file or URL in the user's preferred application. 238Command yes |Print a string until interrupted 239