Hack 1. Use CDPATH to define the base directory for cd command

by Ramesh

If you are frequently performing cd to subdirectories of a specific parent directory, you can set the CDPATH to the parent directory and perform cd to the subdirectories without giving the parent directory path as explained below.

[ramesh@dev-db ~]# pwd
/home/ramesh

[ramesh@dev-db ~]# cd mail
-bash: cd: mail: No such file or directory

[Note: This is looking for mail directory under current directory]

[ramesh@dev-db ~]# export CDPATH=/etc
[ramesh@dev-db ~]# cd mail
/etc/mail

[Note: This is looking for mail under /etc and not under current directory]

[ramesh@dev-db /etc/mail]# pwd
/etc/mail

To make this change permanent, add export CDPATH=/etc to your ~/.bash_profile

Similar to the PATH variable, you can add more than one directory entry in the CDPATH variable, separating them with : , as shown below.

$ export CDPATH=.:~:/etc:/var

This hack can be very helpful under the following situations:

  • Oracle DBAs frequently working under $ORACLE_HOME, can set the CDPATH variable to the oracle home
  • Unix sysadmins frequently working under /etc, can set the CDPATH variable to /etc
  • Developers frequently working under project directory /home/projects, can set the CDPATH variable to /home/projects
  • End-users frequently accessing the subdirectories under their home directory, can set the CDPATH variable to ~ (home directory)

{ 2 comments… read them below or add one }

1 Francois Begin April 5, 2010 at 1:00 pm

The order in which you define the directories with CDPATH determines where you end up. For instance, assume you have set CDPATH to this

CDPATH=.:/var:~

If you are located at the root of the filesystem (/) and type in ‘cd tmp’, you will end up in /tmp since the ‘cd’ command matches ‘./tmp’ first.

If you were in /etc when you type ‘cd tmp’, then ‘cd’ would look for ‘./tmp’ i.e. ‘/etc/tmp’ first. If not found, it would then look for /var/tmp. If not found, it would finally look for ~/tmp.

Just keep that in mind if you have multiple entries in CDPATH and try to go into a subdirectory with a common name such as ‘log’, ‘tmp’, etc.

2 Jonathan January 19, 2011 at 6:54 pm

Exporting CDPATH has the unfortunate side effect of breaking some utilities implemented as shell scripts. (There are two effects shell script authors might not be prepared for: “cd” suddenly jumps to unexpected directories, and it writes text to the standard output.)

By contrast, a simple

if test “${PS1+set}”; then CDPATH=whatever; fi

in .bashrc sets CDPATH in interactive shells, without exporting it to noninteractive scripts.

From here

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