Quote Originally Posted by argo
In other word shouldn't there location be specified?
While it is best to put the full path in to make it clear what is being run it is not necessary. In the instance where no path is given most operating systems will search for the executable using the PATH environment variable, and run the first match it comes across.

This is likely to be set in one of the startup scripts, you can search for it by doing a "grep PATH= /etc/rc.d/rc.*". To display the current setting you can use "echo $PATH". You will find that many of the system "bin" directories will be specified in this "search path".

A quick example would be: If PATH=/usr/bin:/usr/local/bin:/var/hack/bin, and the command "cron" was issued, then it would first try /usr/bin/cron, then /usr/local/bin/cron and finally /var/hack/bin/cron. If non of these matched then it would return with an "unknown command" error.

Hope this helped.