====== Terminal Command Reference ======

===== System Info =====
^ Command     ^ Definition^ 
| ''**date**''           | Show the current date and time       | 
| ''**cal**''   | Show this month's calendar           | 
| ''**uptime**''   | how current uptime           | 
| ''**w**''        | Display who is online        | 
| ''**whoami**''   | Who you are logged in as     | 
| ''**finger user**''   | Display information about user           | 
| ''**uname -a**''   | Show kernel information           | 
| ''**cat /proc/cpuinfo**''   | CPU information           | 
| ''**cat /proc/meminfo**''   | Memory information          | 
| ''**df -h**''   | Show disk usage          | 
| ''**du**''   | Show directory space usage   | 
| ''**free**''   | Show memory and swap usage          |

===== Keyboard Shortcuts =====

^ Command     ^ Definition^ 
| ''**Enter**''           | Run the command       | 
| ''**Up Arrow**''           | Show the previous command       | 
| ''**Ctrl + R**''           | Allows you to type a part of the command you're looking for and finds it | 
| ''**Ctrl + Z**''    | Stops the current command, resume with fg in the foreground or bg in the background | 
| ''**Ctrl + C**''| Halts the current command, cancel the current operation and/or start with a fresh new line| 
| ''**Ctrl + L**''           | Clear the screen    | 
| ''**command | less**'' |Allows the scrolling of the bash command window using Shift + Up Arrow and Shift + Down Arrow| 
| ''**!!**''           | Repeats the last command      | 
| ''**command  !$**''           | Repeats the last argument of the previous command| 
| ''**Esc + .**'' (a period) | Insert the last argument of the previous command on the fly, which enables you to edit it before executing the command| 
| ''**Ctrl + A**''           | Return to the start of the command you're typing       | 
| ''**Ctrl + E**''           | Go to the end of the command you're typing       | 
| ''**Ctrl + U**''           | Cut everything before the cursor to a special clipboard, erases the whole line| 
| ''**Ctrl + K**''           | Cut everything after the cursor to a special clipboard       | 
| ''**Ctrl + Y**''           | Paste from the special clipboard that Ctrl + U and Ctrl + K save their data to       | 
| ''**Ctrl + T**''           | Swap the two characters before the cursor (you can actually use this to transport a character from the left to the right, try it!)       | 
| ''**Ctrl + W**''           | Delete the word / argument left of the cursor in the current line       | 
| ''**Ctrl + D**''           | Log out of current session, similar to exit       | 

===== Learn the Commands =====

'''apropos subject''' – List manual pages for subject

'''man -k keyword''' – Display man pages containing keyword

'''man command''' – Show the manual for command

'''man -t man | ps2pdf''' - > man.pdf  – Make a pdf of a manual page

'''which command''' – Show full path name of command

'''time command''' – See how long a command takes

'''whereis app''' – Show possible locations of app

'''which app''' – Show which app will be run by default; it shows the full path

===== Searching =====

'''grep pattern files''' – Search for pattern in files

'''grep -r pattern dir''' – Search recursively for pattern in dir

'''command | grep pattern''' – Search for pattern in the output of command

'''locate file''' – Find all instances of file

'''find / -name filename''' – Starting with the root directory, look for the file called filename

'''find / -name ”*filename*”''' – Starting with the root directory, look for the file containing the string filename

'''locate filename''' – Find a file called filename using the locate command; this assumes you have already used the command updatedb (see next)

'''updatedb''' – Create or update the database of files on all file systems attached to the Linux root directory

'''which filename''' – Show the subdirectory containing the executable file  called filename

'''grep TextStringToFind /dir''' – Starting with the directory called dir, look for and list all files containing TextStringToFind

===== File Permissions =====

'''chmod octal file''' – Change the permissions of file to octal, which can be found separately for user, group, and world by adding: 4 – read (r), 2 – write (w), 1 – execute (x)

Examples:

'''chmod 777''' – read, write, execute for all

'''chmod 755''' – rwx for owner, rx for group and world

For more options, see man chmod.

===== File Commands =====

'''ls''' – Directory listing

'''ls -l''' – List files in current directory using long format

'''ls -laC''' – List all files in current directory in long format and display in columns

'''ls -F''' – List files in current directory and indicate the file type

'''ls -al''' – Formatted listing with hidden files

'''cd dir''' – Change directory to dir

'''cd''' – Change to home

'''mkdir dir''' – Create a directory dir

'''pwd''' – Show current directory

'''rm name''' – Remove a file or directory called name

'''rm -r dir''' – Delete directory dir

'''rm -f file''' – Force remove file

'''rm -rf dir''' – Force remove an entire directory dir and all it’s included files and subdirectories (use with extreme caution)

'''cp file1 file2''' – Copy file1 to file2
'''
cp -r dir1 dir2''' – Copy dir1 to dir2; create dir2 if it doesn't exist

'''cp file /home/dirname''' – Copy the filename called file to the /home/dirname directory

'''mv file /home/dirname''' – Move the file called filename to the /home/dirname directory

'''mv file1 file2''' – Rename or move file1 to file2; if file2 is an existing directory, moves file1 into directory file2

'''ln -s file link''' – Create symbolic link link to file

'''touch file''' – Create or update file

'''cat > file''' – Places standard input into file

'''cat file''' – Display the file called file

'''more file''' – Display the file called file one page at a time, proceed to next page using the spacebar

'''head file''' – Output the first 10 lines of file

'''head -20 file''' – Display the first 20 lines of the file called file

'''tail file''' – Output the last 10 lines of file

'''tail -20 file''' – Display the last 20 lines of the file called file

'''tail -f file''' – Output the contents of file as it grows, starting with the last 10 lines

===== Compression =====

'''tar cf file.tar files''' – Create a tar named file.tar containing files

'''tar xf file.tar''' – Extract the files from file.tar

'''tar czf file.tar.gz files''' – Create a tar with Gzip compression

'''tar xzf file.tar.gz''' – Extract a tar using Gzip

'''tar cjf file.tar.bz2''' – Create a tar with Bzip2 compression

'''tar xjf file.tar.bz2''' – Extract a tar using Bzip2

'''gzip file''' – Compresses file and renames it to file.gz

'''gzip -d file.gz''' – Decompresses file.gz back to file

===== Printing =====

'''/etc/rc.d/init.d/lpd start''' – Start the print daemon

'''/etc/rc.d/init.d/lpd stop''' – Stop the print daemon

'''/etc/rc.d/init.d/lpd status''' – Display status of the print daemon

'''lpq''' – Display jobs in print queue

'''lprm''' – Remove jobs from queue

'''lpr''' – Print a file

'''lpc''' – Printer control tool

'''man subject | lpr''' – Print the manual page called subject as plain text

'''man -t subject | lpr''' – Print the manual page called subject as Postscript output

'''printtool''' – Start X printer setup interface

===== Network =====

'''ifconfig''' – List IP addresses for all devices on the local machine

'''iwconfig''' – Used to set the parameters of the network interface which are specific to the wireless operation (for example: the frequency)

'''iwlist''' – used to display some additional information from a wireless network interface that is not displayed by iwconfig

'''ping host''' – Ping host and output results

'''whois domain''' – Get whois information for domain

'''dig domain''' – Get DNS information for domain

'''dig -x host''' – Reverse lookup host

'''wget file''' – Download file

'''wget -c file''' – Continue a stopped download

===== SSH =====

'''ssh user@host''' – Connect to host as user

'''ssh -p port user@host''' – Connect to host on port port as user

'''ssh-copy-id user@hos'''t – Add your key to host for user to enable a keyed or passwordless login

===== User Administration =====

'''adduser accountname''' – Create a new user call accountname

'''passwd accountname''' – Give accountname a new password

'''su''' – Log in as superuser from current login

'''exit''' – Stop being superuser and revert to normal user

===== Process Management ======

'''ps''' – Display your currently active processes

'''top''' – Display all running processes

'''kill pid''' – Kill process id pid

'''killall proc''' – Kill all processes named proc (use with extreme caution)

'''bg''' – Lists stopped or background jobs; resume a stopped job in the background

'''fg''' – Brings the most recent job to foreground
'''fg n''' – Brings job n to the foreground


===== Installation from source =====

'''./configure'''

'''make'''

'''make install'''

'''dpkg -i pkg.deb''' – install a DEB package (Debian / Ubuntu / Linux Mint)

'''rpm -Uvh pkg.rpm''' – install a RPM package (Red Hat / Fedora)

===== Stopping & Starting =====

'''shutdown -h now''' – Shutdown the system now and do not reboot

'''halt''' – Stop all processes - same as above

'''shutdown -r 5''' – Shutdown the system in 5 minutes and reboot

'''shutdown -r now''' – Shutdown the system now and reboot

'''reboot''' – Stop all processes and then reboot - same as above

'''startx''' – Start the X system