Why and How To Customize a UNIX / Linux User Account?
Q. Can you tell more about UNIX user account customization along with some sample configuration?
A. Usually useradd / adduser and passwd commands are used for creating an entry for a user in /etc/passwd, /etc/shadow and /etc/group files. However, adding user in files may not provide all the functionality needed. You need to set user customization by modifying various scripts located at /etc or ~/ (user home directory). These scripts executed at the start of every console (text based) login or ssh session to setup the user's environment.
Typical UNIX / Linux login scenario
User login / SSH Login
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System login script /etc/profile
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Personal login script $HOME/.profile
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Shell startup script $HOME/.bash_profile $HOME/.shrc
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User logged in (login complete)
You can add system wide customization using /etc/profile file. End users can manage their own profile / custom environment using personal login script or shell startup script.
Why customize a UNIX / Linux / BSD user account?
Following are few common examples:
- Set the JDK / JVM / PATH variables
- Set the user's terminal type
- Customize the user's prompt
- Set a default text editor
- Setup historyfile size and location
- Run reports as soon as you log into account etc
- Set a command line shortcuts and aliases
Sample Customization
$ cat ~/.bash_profile
Output:
export TERM=xterm # my terminal type
export PS1="$ " # my sweet prompt
export JAVA_HOME=/opt/jvm/java-6-sun #for java
export PATH=$PATH:$JAVA_HOME/bin:/home/vivek/bin # my binary file search path
export EDITOR=vim # my editor
export HISTSIZE=100 # history file size
export HISTFILE=~/.cmd_history # history file location
umask 077 # my umask
ulimit -c 0 # unlimited core file
# some shell variables
set -o noclobber
set -o physical
shopt -s cdspell
shopt -s extglob
shopt -s dotglob
shopt -s cmdhist
shopt -s lithist
shopt -s progcomp
shopt -s checkhash
shopt -s histreedit
shopt -s promptvars
shopt -s cdable_vars
shopt -s checkwinsize
shopt -s hostcomplete
shopt -s expand_aliases
shopt -s interactive_comments
bind '"\C-t": possible-completions' # replaces 'transpose-chars'
bind '"\M-t": menu-complete' # replaces 'transpose-words'
View environment variables list
Simply user env command, enter:
$ env
/etc/skel directory to push configuration to user
By default all files from /etc/skel are copied to the new user's home directory; when a new user account created. There are few files included in /etc/skel/ by default.
- /etc/skel/.bash_logout
- /etc/skel/.bashrc
- /etc/skel/.profile
- /etc/skel/.cshrc
- /etc/skel/.exrc (/etc/skel/.vimrc)
You can also create or copy existing scripts in /etc/skel. For example copy /usr/share/vim/vimrc to /etc/skel/.vimrc
# cp /usr/share/vim/vimrc /etc/skel/.vimrc
Now file /etc/skel/.vimrc will be copied when a new user account created.
Suggested readings:
- man pages bash, csh, ksh, sh
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Related Other Helpful FAQs:
- Can I create another root user account in Linux / UNIX?
- Linux locking an account
- Linux add a user using command line tools
- How to add a ssh user in FreeBSD server
- FreeBSD locking an account
Discussion on This FAQ
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Tags: /etc/profile, /etc/skel, account customization, bash user account customize, default text editor, export ps1, export term, login system, path variables, search path, shell user account customize, shell variables, system login script, terminal type, umask, ~/.bash_profile, ~/.profile
February 4th, 2008 at 1:43 pm
Hi,
The last few sentences talk of /etc/.vimrc and they should be /etc/skel/.vimrc
Cheers,
Craig.
February 4th, 2008 at 2:00 pm
Craig,
Thanks for the heads up.
February 8th, 2008 at 11:52 am
To customize adding/deleting users even more but still use the built-in tools, adduser/deluser can be used.
It has config files and custom scripts that can be run automatically when a user is added/deleted:
/etc/adduser.conf
/etc/deluser.conf
/usr/local/sbin/adduser.local
/usr/local/sbin/deluser.local
HTH.
February 26th, 2008 at 12:00 pm
Your answers are crips but explicit. They are very educational and helpful