Check the open FD limit for a given process in Linux
file-descriptor, limit, linux, operating-system, scripting
Solution
Count the entries in `/proc/<pid>/fd/`. The hard and soft limits applying to the process can be found in `/proc/<pid>/limits`.
Problem
I recently had a Linux process which “leaked” file descriptors: It opened them and didn't properly close some of them. If I had monitored this, I could tell – in advance – that the process was reaching its limit. Is there a nice, Bash or Python way to check the FD usage ratio for a given process in a Ubuntu Linux system? EDIT: I now know how to check how many open file descriptors are there; I only need to know how many file descriptors are allowed for a process. Some systems (like Amazon EC2) don't have the `/proc/pid/limits` file.