Strace is a command line tool which can be used to figure out what is wrong with an errant application running in your Linux system. Some even look at strace as the Swiss army knife of a systems administrator.
Check out how I used strace to troubleshoot a multimedia problem in Ubuntu a long time back.
More recently, Greg Price at the Ksplice blog has written an informative article on strace which explains the use of this troubleshooting tool.
