| 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 |
| 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 |
'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
'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
'chmod octal file' – Change the permissions of file to octal, which can be found separately for user, group, and world by adding: 4 – read ®, 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.
'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
'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
'/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
'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 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
'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
'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
'./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)
'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