Q: I added a new executable to /usr/local/bin. Until I logout and log back in, I'm unable to access the new executable by name from the command line. Why? How do I fix this?
A: Assuming /usr/local/bin is in your PATH environment variable, run the C-Shell command
rehash
From the csh(1) man page, this causes the internal hash table of the contents of the directories in the path variable to be recomputed. This is needed if new commands are added to directories in the path while you are logged in. This should only be necessary if you add commands to one of your own directories, or if a systems programmer changes the contents of one of the system directories.
Note that there's no analog to rehash in the Bourne shell, nor is one needed.
