The LWP suite of Perl modules and applications is a popular choice for developing powerful automated web clients in Perl. However, if you install it under Mac OS X, it could make a dangerous change to your system (if Mac OS X is installed on an HFS+ file system).
LWP creates an executable program called /usr/bin/HEAD. Because the file system is case-insensitive, this ends up replacing the essential Unix utility called /usr/bin/head. After you install LWP, you can rename /usr/bin/HEAD to /usr/bin/HEAD_LWP, and copy /usr/bin/head from your Mac OS X install CD. I learned about this problem from:
http://www.mail-archive.com/dev@perl.apache.org/msg00492.html
- Brian
Mac OS X Hints
http://hints.macworld.com/article.php?story=20010603142727786