Document Text Contents
Page 81
Topic 111: Administrative Tasks
1.111.2 Tune the user environment and system
environment variables
Description: Candidate should be able to modify global and user profiles. This includes
setting environment variables, maintaining skel directories for new user accounts and
setting command search path with the proper directory.
Weight: 3
Key files, terms, and utilities include:
/etc/profile
/etc/skel
env
export
set
unset
Shell configuration
Each time a user logs-in (via the login program) a shell is started. Which shell will be
started is defined in the last field of /etc/passwd. Depending on the shell started, some
configuration files will be executed to prepare the shell's environment. Some
configurations are system-wide and others are unique to each individual user.
Here is the list of configuration files read for different login-shells:
Bourne Again Shell Korn Shell TC-Shell
System wide /etc/profile
/etc/csh.cshrc
/etc/csh.login
Individual
Users
~/.bash_profile
~/.bash_login
~/.profile
~/.tcshrc or ~/.cshrc
~/.history
~/.login
~/.cshdirs
A non-login bash shell reads only ~/.bashrc and inherits all the environment parameters
from the parent process.
Although already mentioned in the previous chapters, there is also a difference between
an interactive shell and a non-interactive shell:
Interactive:
Presents a prompt for the user to enter commands. The shell will read its configuration
files depending on whether it is a login or non-login shell. (see above)
Non-interactive:
Is normally run as a sub-shell and will not read any configuration file. It depends
entirely on inheritance from the parent process.
Parameters defined for bash in configuration files
The following parameters are defined either in /etc/profile for all users or in one of the
files defining the individual bash settings:
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Topic 111: Administrative Tasks
1.111.2 Tune the user environment and system
environment variables
Description: Candidate should be able to modify global and user profiles. This includes
setting environment variables, maintaining skel directories for new user accounts and
setting command search path with the proper directory.
Weight: 3
Key files, terms, and utilities include:
/etc/profile
/etc/skel
env
export
set
unset
Shell configuration
Each time a user logs-in (via the login program) a shell is started. Which shell will be
started is defined in the last field of /etc/passwd. Depending on the shell started, some
configuration files will be executed to prepare the shell's environment. Some
configurations are system-wide and others are unique to each individual user.
Here is the list of configuration files read for different login-shells:
Bourne Again Shell Korn Shell TC-Shell
System wide /etc/profile
/etc/csh.cshrc
/etc/csh.login
Individual
Users
~/.bash_profile
~/.bash_login
~/.profile
~/.tcshrc or ~/.cshrc
~/.history
~/.login
~/.cshdirs
A non-login bash shell reads only ~/.bashrc and inherits all the environment parameters
from the parent process.
Although already mentioned in the previous chapters, there is also a difference between
an interactive shell and a non-interactive shell:
Interactive:
Presents a prompt for the user to enter commands. The shell will read its configuration
files depending on whether it is a login or non-login shell. (see above)
Non-interactive:
Is normally run as a sub-shell and will not read any configuration file. It depends
entirely on inheritance from the parent process.
Parameters defined for bash in configuration files
The following parameters are defined either in /etc/profile for all users or in one of the
files defining the individual bash settings:
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