Unix Cheetsheet! These cheat sheets are the most command and practises I need to work more on them to remember them. There isn't everything here included because I know most of the simple ones.

Unix.md

SHORTCUTS

• ctrl+a — move cursor to beginning of line
• ctrl+e — move cursor to end of line
• ctrl+u — clear to beginning of line
• ctrl+k — clear to end of line

FILE SYSTEM

• cp -r dir1 dir - copy directory dir1 to dir2
• ln -s file link — create soft symbolic link to file (soft)
• ln file link — create hard symbolic link to file (hard)
• less file — view file with page navigation
• head file — output the first 10 lines of file
• tail file — output the last 10 lines of file
• tail -f file — output the contents of file as it grows

SYSTEM

• shutdown — shut down machine
• reboot — restart machine
• df — show disk usage
• du — show directory space usage

SEARCHING

• grep pattern files — search for pattern in files
• grep -r pattern dir — search recursively for pattern in dir
• grep -rn pattern dir — search recursively for pattern in dir and show the line number found
• grep -r pattern dir --include='*.ext — search recursively for pattern in dir and only search in files with .ext extension
• grep -E pattern files — search for pattern using Extended regexp in files
• command | grep pattern — search for pattern in the output of command
• find file* — find all instances of file in real system
• find . -iname 'string*' - find file case insensitive with a pattern
• find -L . -iname '*.js' -exec chmod 744 {} \; - find js files and change mode to 644 within this directory
• find /var/log/ -iname '*.tmp' -delete - find .tmp files within that directory and delete them
• locate file — find all instances of file using indexed database built from the updatedb command. Much faster than find
• sed -i 's/day/night/g' file — find all occurrences of day in a file and replace them with night - s means substitude and g means global - sed also supports regular expressions
• sed -i -- 's/old/new/g' */**(.D) find and replace old string with new string withing this folder and all its subfolder

PROCESS MANAGEMENT

• ps — display your currently active processes
• top — display all running processes
• kill pid — kill process id pid
• kill -9 pid — force kill process id pid

NETWORKING

• scp user@host:file dir — secure copy a file from remote server to the dir directory on your machine
• scp file user@host:dir — secure copy a file from your machine to the dir directory on a remote server
• scp -r user@host:dir dir — secure copy the directory dir from remote server to the directory dir on your machine
• ssh -p port user@host — connect to host on port as user
• ssh-copy-id user@host — add your key to host for user to enable a keyed or passwordless login
• ping host — ping host and output results
• whois domain — get information for domain
• dig domain — get DNS information for domain
• dig -x host — reverse lookup host
• lsof -i tcp:1337 — list all processes running on port 1337

COMPRESSION

• tar cvzf file.tar.gz files — create a tar with Gzip compression
• tar cafxz file.tar.gz — extract a tar using Gzip

PERMISSIONS

• chmod ugo file — change permissions of file to ugo - u is the user's permissions, g is the group's permissions, and o is everyone else's permissions. The values of u, g, and o can be any number between 0 and 7.
• x = 1
• w = 2
• r = 4
• u = user
• g = group
• o = other

Examples

• u+rwx
• g=r
• 0-rwx
• 777 = a+rwx

USERS & GROUPS

• sudo adduser username - will add user and then you'll need to enter password
• su username - switch user
• passwd - updates the password
• chsh - changes the shell
• chfn - update user information
• usermod - update user settings like their username and home directory
• deluser - deletes users

BACKGROUND & FORGROUND JOBS AND TASKS

• YOUR COMMAND & - start the task in the background
• bg %1 - send job to the background
• fg %1 - bring job to the forground
• CTRL + z - in vim suspends the text editor and jumps out, you then have to type fg %1 to get back to it