Linux utilities and Basic Commands

The following is a list of commonly used commands which are organized under different categories for understanding and ease of use. Keys proceeded by a ^ character are CONTROL key combinations.

Linux utilities and Basic Commands

^h backspace erase previously typed character 
^u erase entire line of input so far typed 
^d end-of-input for programs reading from terminal 
^s stop printing on terminal 
^q continues printing on terminal 
^z currently running job; restart with bg or fg 
 DEL, ^c kill currently running program and allow clean-up before exiting 
^\ emergency kill of currently running program with no chance of cleanup

Login and Authentication 

Login access computer; start interactive session

Logout disconnect terminal session

Passed change local login password; you MUST set a non-trivial password Information

·        date show date and time

·        history list of previously executed commands

·        pine send or receive mail messages

·        msgs display system messages

·        man show on-line documentation by program name

·        info on-line documentation for GNU programs

·        w, who who is on the system and what are they doing

·        who am i who is logged onto this terminal

·        top show system status and top CPU-using processes

·        uptime show one line summary of system status

·        finger find out info about a user@system

File Management

·        cat                  combine files

·        cp                    copy files

·        ls                     list files in a directory and their attributes

·        mv                  change file name or directory location

·        rm                   remove files

·        ln                     create another link (name) to a file

·        chmod           set file permissions

·        des                 encrypt a data file with a private key

·        find                 find files that match specified criteria

Display Contents of Files

·        cat                  copy file to display device

·        vi                     screen editor for modifying text files

·        more              show text file on display terminal with paging control

·        head               show first few lines of a file(s)

·        tail                  show last few lines of a file; or reverse line order Operating System

·        grep               display lines that match a pattern

·        lpr                   send file to line printer

·        pr                    format file with page headers, multiple columns etc.

·        diff                  compare two files and show differences

·        cmp                compare two binary files and report if different

·        od                   display binary file as equivalent octal/hex codes

·        file                  examine file(s) and tell you whether text, data, etc.

·        wc                   count characters, words, and lines in a file