UNIX commands

Kaustubh Kesarkar

— 3 min read
UNIX commands
Photo by Gabriel Heinzer / Unsplash

Basic commands

  • su: login as super user (e.g. root)
  • pwd: current directory
  • ls: list files
  • ls -l: list files with detail info
  • bunzip2 [FILE_NAME]: decompress file at same location
  • cp [FILE_1] [FILE_2]: copy file1 to a file called file2
  • mv [FILE_1] [FILE_2]: (move) rename file1 to the name file2
  • mv [FILE_1] /[FOLDER_NAME]: move file1 to the [FOLDER_NAME] directory
  • rm *: deletes everything in a subdirectory (http://cmgm.stanford.edu/classes/unix/rm.html)
  • rm -r *: deletes everything in directory
  • rm test.txt: removes only file with a name "test.txt" on the end
  • tail -500 FILE_NAME | less: see last 500 lines of files
  • cat [FILE_NAME]: view file

Size

  • df -k: disk size
  • df -g: disk size
  • df -h: disk size
  • du -s [FOLDER_NAME]: folder size info
  • du -sh ./: current directory size
  • du -sh -- *(D) | sort -k1n: order parent folder by size in ascending order
  • ls -l | grep ^- | sort -nr -k 5: order files as per size

Basic network commands

  • ifconfig: similar to ipconfig (display network interface parameters)
  • hostname: get machine's name
  • /etc/init.d/network restart: restart network

Install

  • rpm -ivh: install rpm bin file

Init file

Terminal

  • tty: to check terminal
  • ps -ef | grep java: check the java processes
  • kill -9 <process_id>: <process_id> is returned by prev command.

User

  • startx: start GUI
  • useradd <user>: create new user
  • passwd <user>: change password for user
  • groupadd <groupname>: create new group
  • usermod -g <groupname> <user>: Assign a user to a primary group
  • usermod -G <groupname> <user>: Assign a user to secondary groups
  • who am i: current user

vi Editor

  • vi [FILE_NAME]: Open or edit a file.
  • Esc: Switch to Command mode.
  • oo / o: insert new line after current line
  • OO / O: insert new line before curren line
  • i: Switch to Insert mode.
  • [ESC] i ENTER: insert into file to location
  • :w: Save and continue editing
  • :wq or ZZ: Save and quit/exit vi
  • :x: to file save
  • :q!: Quit vi and do not save changes
  • yy: Yank (copy) a line of text
  • p: Paste a line of yanked text below the current line
  • o: Open a new line under the current line
  • O: Open a new line above the current line
  • A: Append to the end of the line
  • a: Append after the cursor’s current position
  • I: Insert text at the beginning of the current line
  • b: Go to the beginning of the word
  • e: Go to the end of the word
  • x: Delete a single character
  • dd: Delete an entire line
  • [X]dd: Delete X number of lines
  • [X]yy: Yank X number of lines
  • G: Go to the last line in a file
  • [X]G: Go to line X in a file
  • gg: Go to the first line in a file
  • :num: Display the current line’s line number
  • h: Move left one character
  • l: Move right one character
  • j: Move down one line
  • k: Move up one line

Set ENV

  • vi ~/.bash_profile: env variable setup file
  • source ~/.bash_profile: export env variables to system
  • export JAVA_HOME=/root/java/jdk1.7.0_45
  • export MAVEN_HOME=/root/java/apache-maven-3.1.1
  • export ANT_HOME=/root/java/apache-ant-1.9.2
  • export PATH=$PATH:${JAVA_HOME}/bin:${MAVEN_HOME}/bin:${ANT_HOME}/bin

Increase swap size

  • dd if=/dev/zero of=/.swapfile bs=1M count=2048
  • mkswap -v1 /.swapfile
  • swapon /.swapfile

Miscellaneous

Read more