About Basic 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

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
    Command(s): set setenv source

  • Finger allows you to check the user information for an

    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
    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

    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
    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

    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