I have read a little on lsof. I want to know if this is a good tool to use. - I have software mounted accross the network for C compiler - When i try to unmount the files it fails. Another process(es) are using these files. - How can I find out what process is using these files? === More detail === My Development server will not shutdown properly when the prod compiler (/usr/ccs) directory is mounted across the network to the development server. The "umount /usr/ccs" command does not work. There is an error message (1861-15 16) that could not be found in any documentation. The dev server has to be powered down manually because the "shutdown -Fr" command to reboot the server does not work. The server seems to hang. It appears that the nfs daemons are shutdown BEFORE the umounting of all the drives. The server doesn't know what to do so it hangs. Will lsof help find out what is causing this problem? Is there anything else I could use?

Try: lsof -i | egrep "COMMAND|LISTEN|UDP" Jerry

Have you tried using "fuser" on the files that are complained as "in use"? The fuser command usage is: fuser filename The fuser is available in /usr/sbin/fuser in HPUX. If you do not have root access you can copy the fuser to /tmp, chmod 755 /tmp/fuser on it and then execute it as /tmp/fuser filename to check which process is using this file.