This list of useful and frequently used UNIX commands is a good reference for someone who is new to UNIX/LINUX Operating System. The most commonly used and basic Unix commands and what they do are listed below. Use the “man” command to find the usage and details of any particular command e.g. prompt>man cp. Using “man cp” on the command prompt will display the details and usage of the copy (cp) command.
File/Directory operation related Unix Commands
- cp – copy a file
- mv – move or rename files or directories
- tar – create and use archives of files
- gzip – compress a file
- ftp – file transfer program
- lpr – print out a file
- mkdir – make a directory
- rm – remove files or directories
- rmdir – remove a directory
- mount – attaches a file system to the file system hierarchy at the mount_point, which is the pathname of a directory.
- umount – unmounts a currently mounted file system.
Navigational type Unix Commands
- cd – change directory
- pwd – display the name of your current directory
- ls – list names of files in a directory
Disk, File and Folder Size/Usage
- du – Use this command to see the size/usage of the folder you are in. Example usage: du -sk *
- df – Report file system disk space usage. Example usage: df -k
Display file content
- cat – concatenate and display files.
- more – The more utility is a filter that displays the contents of a text file on the terminal, one screenful at a time.
- less – Less is a program similar to more (1), but which allows backward movement in the file as well as forward movement. Also, less does not have to read the entire input file before starting,so with large input files it starts up faster than text editors like vi
- vi – The vi (visual) utility is a display-oriented text editor.
- nano – nano is a small, free and friendly editor.
- find – find files of a specified name or type.
- grep – searches files for a specified string or expression.
- top – Top displays the top 10 processes on the system and periodically updates this information. Raw cpu percentage is used to rank the processes.
- chmod – change the permissions of a file or a directory.
- ps – The ps command prints information about active processes.
- kill – kill a process.
- date – display the current date and time.
- cal – The cal utility writes a Gregorian calendar to standard output.
- diff – display differences between text files.
- man – The man command displays information from the reference manuals.
- help – The help utility retrieves information to further explain errors messages and warnings from SCCS commands.
If I have missed any frequently used and useful UNIX command(s) to list on this page then please leave your suggestion in the comments area below.