I have a daemon process and I want to know what files it has open (and ideally what its CWD is). Is there any shell command that can tell me that?
I do love
lsof, but I think it's overkill for a simple question like this. The
/proc filesystem contains everything you want to know. Perhaps an example would be best:
# ps ax|grep tail 7196 pts/4 S+ 0:00 tail -f /var/log/messages 8773 pts/0 R+ 0:00 grep tail # ls -l /proc/7196/cwd lrwxrwxrwx 1 insyte insyte 0 2009-07-29 19:05 /proc/7196/cwd -> /home/insyte # ls -l /proc/7196/fd total 0 lrwx------ 1 insyte insyte 64 2009-07-29 19:05 0 -> /dev/pts/4 lrwx------ 1 insyte insyte 64 2009-07-29 19:05 1 -> /dev/pts/4 lrwx------ 1 insyte insyte 64 2009-07-29 19:02 2 -> /dev/pts/4 lr-x------ 1 insyte insyte 64 2009-07-29 19:05 3 -> /var/log/messages
So as you can see, the
/proc/$PID directory contains a symlink called "cwd" that links the the CWD of the process. The same is true for the open filedescriptors listed in
/proc/$PID hierarchy contains a wealth of information about all running processes. Worth poking around in!
If you have the command lsof available [whcih most *nix flavors do] you would use:
lsof -p NNN
to list files open by process NNN. I haven't used BSD in a while but from memory fuser is a close parallel to lsof.
I'm not sure of a command to find the cwd of a process but on Linux cwd is symlinked into the /proc directory of the process ie. /proc/NNN/cwd.