About UNIX Commands

The UNIX operating system is case sensitive. In general, commands in UNIX are lower case. Commands can include three parts: a command, an option, and an argument.

• A command is a word or group of characters that UNIX recognizes as a request to perform a specific task.
• An option, as the name implies, is not mandatory. Options give extra functions to a command; they are always preceded by a dash (-).
• An argument is a variable supplied by the user. Often, it represents the name of a file or directory targeted for action.

For example, the UNIX command ls -l first.file uses the command ls to request a listing, the option l to specify a long listing, and the argument first.file to only list information about the file named first.file.

Customizing Your Unix Environment

• Aliases allow you to define a shortcut for a command or series of commands.

  Command(s): alias

• Customization allows you to set parameters for your shell and sessions.

  Command(s): set setenv source

• Finger allows you to check the user information for an account.

  Command(s): finger chfn

General Account Usage

• Printing from your Unix account.

  Command(s): lpr lpq lprm enscript printers file

• Process Control allows you to list and manage processes running under your account.

  Command(s): ps kill bg fg stop jobs

• Quota manages the limits placed on the amount of disk space you can use. Commands allow you to check your current usage and quota.

  Command(s): quota ls du

File and Directory Commands

• Directory commands allow you to create, remove, and navigate UNIX directories.

  Command(s): ls mkdir rmdir rm cd pwd cp mv pushd popd dirs

• File commands allow you to create, remove, and view files in UNIX.

  Command(s): ls rm mv cp more less cat file diff

• File and Directory Permissions allow you to add/remove access to files and directories in your account for other users.

  Command(s): chmod

• Access Control Lists allow you to give specific users (one or more) access to a single file and/or directory in your account.

  Command(s): setfacl getfacl

File Compression and Transfer

• Tar is a file archiving command that allows you to bundle a number of files and/or directories together into a single file that can be easily transferred between computers.

  Command(s): tar

• File Compression allows you to reduce the size of a file for storage or transfer.

  Command(s): compress uncompress pack unpack zip unzip gzip gunzip zcat zmore zdiff zcmp gzexe zgrep

• File Transfer commands allow you to move files between systems.

  Command(s): ftp kermit xyzmodem rcp

Text File Searching and Manipulation

• Grep commands allow you to search text files for a particular expression (text string).

  Command(s): grep agrep egrep fgrep zgrep

• Filtering Text Files can be used to retrieve, replace or remove certain text strings in a UNIX file or group of files.

  Command(s): awk sed grep

Online Help

• Learn provides an interactive introduction/tutorial to the UNIX system.

  Command(s): learn

• Man Pages provide descriptions and usage information for UNIX commands. Information about any command listed on this page can be found.

  Command(s): man apropos help whatis