TABLE 2-5
Bash Configuration Files
File
Description
/etc/profile
Sets up user environment information for every user. It is executed when you first
log in. This file provides values for your path, as well as setting environment
variables for such things as the location of your mailbox and the size of your history
files. Finally, /etc/profile gathers shell settings from configuration files in the
/etc/profile.d
directory.
/etc/bashrc
Executes for every user who runs the bash shell, each time a bash shell is opened. It
sets the default prompt and may add one or more aliases. Values in this file can be
overridden by information in each user's ~/.bashrc file.
~/.bash_profile
Used by each user to enter information that is specific to his or her own use of the
shell. It is executed only once, when the user logs in. By default it sets a few
environment variables and executes the user's .bashrc file.
~/.bashrc
Contains the information that is specific to your bash shells. It is read when you log
in and also each time you open a new bash shell. This is the best location to add
environment variables and aliases so that your shell picks them up.
~/.bash_logout
Executes each time you log out (exit the last bash shell). By default, it simply clears
your screen.
To change the
/etc/profile
or
/etc/bashrc
files, you must be the root user. Users can change
the information in the
$HOME/.bash_profile
,
$HOME/.bashrc
, and
$HOME/.bash_logout
files in their own home directories.
The following sections provide ideas about items to add to your shell configuration files. In
most cases, you add these values to the
.bashrc
file in your home directory. However, if you
administer a system, you may want to set some of these values as defaults for all of your Linux
system's users.
Setting Your Prompt
Your prompt consists of a set of characters that appear each time the shell is ready to accept a com-
mand. The
PS1
environment variable sets what the prompt contains and is what you interact with
most of the time. If your shell requires additional input, it uses the values of
PS2
,
PS3
, and
PS4
.
When your Linux system is installed, often a prompt is set to contain more than just a dollar sign
or pound sign. For example, in Fedora or Red Hat Enterprise Linux, your prompt is set to include
the following information: your username, your hostname, and the base name of your current
working directory. That information is surrounded by brackets and followed by a dollar sign (for
regular users) or a pound sign (for the root user). Here is an example of that prompt:
[chris@myhost bin]$
If you change directories, the bin name would change to the name of the new directory. Likewise,
if you were to log in as a different user or to a different host, that information would change.
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Running Commands from the Shell
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