In my many client engagements, aside from the many and varied utility libraries (I really ought to put my PAUSE id to good use for the better good:-)) and scripts, the more specific uses include:
Automate the system/soak testing of a SAN product - incl. test result gathering and publication
Provide the basis of a customer API Implementation for the aforementioned SAN product
Provide the glue for SMTP/X400 e-mail & LDAP/X500 systems
Implementing X500/LDAP data management (incl. importing/exporting/synchronisation) tools
Synchronise a multitude of disparate client problem databases with a central project problem database tool
Migrate data from (and then subsequently maintain synchronisation between) a SQL Server based software repository & configuration data into a proprietary CM system
Produce/generate intra-net MIS websites
Implement entirely platform neutral make rules (within a ClearCase environment)
Customise/supplement CM tools to better support/fit in with the defined CM process(es)
Automate the unit testing of both *NIX shell script & C utilities
Implement a self-configuring, extensible dirty word search tool for secure websites and e-mails
Implement a bespoke, UNIX ABI compliant packaging toolset
There's undoubtedly more, but the thought of a nice cool pint, or several, ...
:-D
A user level that continues to overstate my experience :-))