Store a directory name to come back to

Put the following alias in your profile to store a directory name to use later on:

alias sd='set \!:1=$cwd'

Example usage:

$ sd mydir
...
$ cd mydir

This method works for csh but not bash. For bash try the following function in your profile:

sd(){ export $1=$PWD; }

Then:

$ sd abc
...
$ cd $abc