1. Objective

1.109.1

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Objective

1.109.1 Customize and use the shell environment Weight 5
Linux Professional Institute Certification — 102

Description of Objective Candidate should be able to customize shell environments to meet users’ needs. This objective includes setting environment variables (e.g. PATH) at login or when spawning a new shell. It also includes writing bash functions for frequently used sequences of commands. Key files, terms, and utilities include: ∼/.bash_profile — sourced when a person logs in ∼/.bash_login — sourced when a person logs in if no ∼/.bash_profile ∼/.profile —

Geoffrey Robertson ge@ffrey.com Nick Urbanik nicku@nicku.org
This document Licensed under GPL—see section 5

sourced when a person logs in if no ∼/.bash_profile or ∼/.bash_login ∼/.bashrc — sourced when a non-login interactive shell starts ∼/.bash_logout — sourced when a person logs out ∼/.inputrc — allows a user to specify keystrokes for commands

2005 July
Outline

function — (Bash built-in command) export — make environment variables available to sub processes env — display environment 1 2 2 3 3 4 set — (Bash built-in command) unset — (Bash built-in command) — remove any definition of an environment variable

Contents
0.1 1 2 3 4 Context . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Objective Bash Configuration Files Aliases Bash functions

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Bash Configuration Files
• When a user logs in to a bash shell the following configuration files are usually executed: /etc/profile System wide profile, common to all users and shells ∼/.bash_profile sourced after /etc/profile at login ∼/.bashrc sourced after ∼/.bash_profile at login

Bash Configuration Files

5 License Of This Document

0.1 Context
Topic 109 Shells, Scripting, Programming and Compiling [8] 1.109.1 Customise and use the shell environment [5]

• Note ∼/.bashrc is executed when any new bash shell is spawned 1.109.2 Customise or Write Simple Scripts [3]

3. Aliases

1.109.1

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5. License Of This Document Bash Functions • $ function look()

1.109.1

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Aliases

Bash Aliases

pwd; ls;

• $ look() { pwd; ls }

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Bash functions
• Functions work similarly to aliases but allow more complex constructions. • They have the following syntax: $ [ function ] NAME() { COMMAND_LIST;} ← • Where function Optional tag NAME() The name of the function COMMAND_LIST The body of the function • Functions may be stored in ∼/.bashrc

• $ function look() {pwd; ls;} Bash Functions • A function that uses a command line argument: $ > > > laps () {← ls -l $1 ps aux | grep ‘/usr/bin/basename $1‘ }

Bash Functions

• Use the laps() function:
$ laps /usr/sbin/sshd ← -rwxr-xr-x 1 root root 276200 Jun 29 01:28 /usr/sbin/sshd root 255 0.0 0.3 2792 1216 ? S Aug31 0:00 /usr/sbin/sshd geoffrey 1187 0.0 0.1 1332 424 pts/1 R 14:39 0:00 grep sshd

Bash Functions • This simple function prints the current working directory and the list of files in it: $ function look() { pwd; ls;} ← • This function would be used like this: $ look ← /home/geoffrey/lpic/general-linux-2/notes CVS _whizzy_gl2.notes.fmt _whizzy_gl2.notes.pag Bash Functions • $ function look() { pwd; ls;} • $ function look { pwd; ls; } • $ look() { pwd; ls;} •$ > > > > look() { pwd; ls; }

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License Of This Document

License Of This Document Copyright c 2005, 2003 Geoffrey Robertson <ge@ffrey.com> and Nick Urbanik <nicku@nicku.org>. Permission is granted to make and distribute verbatim copies or modified versions of this document provided that this copyright notice and this permission notice are preserved on all copies under the terms of the GNU General Public License as published by the Free Software Foundation—either version 2 of the License or (at your option) any later version.