Realpath

realpath is a program to resolve a path to an item in the filesystem. Depending on switches, it can resolve symlinks and ".." elements to produce a simple path, either absolute or relative to the current directory. It can be very handy in scripts or wherever there are multiple paths that could lead to the same file or directory.

Examples
user@mymachine:~$ realpath. # note the dot /home/user

user@mymachine:~$ ln -s /usr/bin ub   user@mymachine:~$ realpath ub/realpath /usr/bin/realpath

Provided by
Not all distributions provide this command, but most (all?) of the ones that do incorporate this from the GNU Coreutils: and use its man page