Virtual Private Server User Guide

Internet and UNIX Basics

Type out the rest of the filename manually; or 

Type the next character (in this case, i) and hit [TAB] again:

> rm testi[TAB]

Efficient use of the tab completion feature of a shell can save you a lot of time and 

keystrokes.

Environment Variables

Another common function of the shell is environment variables. An environment 

variable is a name/value pair that can be read by any program invoked by the 

shell. Here is a list of common environment variables and what they mean:

Variable Description 

USER 

The login name of the current user. 

PATH 

A colon separated list of directories in which the shell looks for 

commands. If a program is in a directory that is not in the user's 

path, the path to the file must be given for the shell to find it. 

SHELL 

The name of the shell you are using. 

EDITOR 

The user s preferred text editor. Programs that need to let you edit 

text will usually use your preferred editor to do so. The default editor 

on your virtual server is pico, but you can change it to whatever 

editor you wish. 

PAGER 

The user s preferred text pager. Programs that display a lot of text 

will often use your preferred pager program to make it easier to 

read. The default text pager is more. 

The method for viewing or setting an environment variable differs somewhat from 

shell to shell. For example, in the C Style shells such as tcsh and csh, you would 

use the "setenv" command to set and view environment variables. Under Bourne 

shells such as sh and bash, you would use the "set" and "export" commands 

instead. For example, to set or modify the EDITOR environment variable, in a csh 

or tcsh shell, a command like this would set EDITOR to /usr/local/bin/vi:

> setenv EDITOR /usr/local/bin/vi

Under Bourne shells:

> 

export EDITOR="/usr/local/bin/vi"

You can also make most shells expand the environment variable by placing a $ 

character in front of it on the command line. For example, echo $USER would 

print out your user name because the shell expands $USER and passes it on to 

the echo command, which prints it on the screen.

Technical Training Department

August 2004

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