Basic Unix Commands

Basic Unix Commands:

The Unix operating system supports many commands. This page represents a list of some of the commands that can be used within the Unix operating system. To get more detailed information on how to use of any of the commands listed, type "man command" at the Unix prompt, where command is the name of a Unix command.

Note: In the listing below, the word files refers to a list of any number of files separated by white space; in the same way, names refers to a list of file or directory names separated by white space and directory (or dir) refers to the name of a file directory.

General apropos command Locate commands by keyword lookup exit Terminate your current session, or shell man command Display the Unix manual page describing a given Unix command

File System Navigation cd Return to your home directory cd directory Change directory to make directory your current directory file files Determine file type ls List the contents of the current directory ls names List the contents of the directories; names can name files and/or directories ls -l List the contents of the directories; names can name files and/or directories in a long format, showing permissions, owner, size, and other file info ls -a List the contents of the directories; names can name files and/or directories all files, including "hidden" files (file names that begin with a dot ".") ls -R List the contents of the directories; names can name files and/or directories recursively, for all subdirectories ls -t List the contents of the directories; names can name files and/or directories in time order (when modified, newest to oldest) rather than in name order pwd Display the name of the current directory, or "print working directory"

File/Directory Manipulation chmod Changes the file permissions on a file compress files Reduces the size of a file uncompress files Restores compressed files to their original form cp file1 file2 Copy file(s) cp files directory Copy file(s) into a directory cp -r dir1 dir2 Copy a directory and, recursively, its subdirectories find Finds a file mkdir directory Create, or "make" a directory mv file1 file2 Move a file or, if file1 and file2 are in the same directory, rename a file mv files directory Move files into a directory mv dir1 dir2 If directory dir2 exists, move dir1 into dir2; otherwise, rename dir1 as dir2 rm files Remove (erase) file(s) rm -r names Remove files, directories, and recursively, any subdirectories rmdir directory Remove directory (directory must be empty)

Data Manipulation cat files Concatenate file(s); you can use cat to display the contents of a file (this is not advisable if the file is a binary file) grep "pattern" files Display all lines in the files that match a pattern more files Display contents of files one screen at a time sort files Order the lines in a file or files alphabetically (this command does not alter the file or files--it merely displays the sorted output to the screen) sort -r files . . . in reverse order sort -n files . . . numerically (puts 2 before 10 instead of after)

Networking/Communications finger user Displays information about a user telnet hostname Connect to another remote system using the telnet protocol talk user Initiate a conversation with another user (end conversation with Control-C). talk works only between machines of the same architecture Miscellaneous !! Repeat last shell command

!string Repeat last shell command that began with string (for example, type "!m" to repeat the last command that began with "m") cal Display a calendar of the current month cal month year Display a calendar of the given month and year. Note that the year must be fully qualified, for example, "1994" and not "94" clear Clears terminal screen date Display the current local date and time echo Displays an argument history Displays listing of recent commands entered who Display a list of users currently logged in