How to get process details from its PID

Question

I have maintained a list of PIDs of processes currently running on my system (Linux). From this, now it would be great if I could get the process details from this PID. I have come over syscall.Getrusage() in Go, but I am not getting the desired results.

What should I do?

Answer 1

This might not be exactly what the asker wanted (there's not much clear info on what type of details are required for each process id), but you can get some details of a task by its pid using the BASH command ps -p $PID (ps being short for process status)

With default options as ps -p $PID this returns:

• PID: echos the process id
• TTY: the name of the controlling terminal (if any)
• TIME: how much CPU time the has process used since execution (e.g. 00:00:02)
• CMD: the command that called the process (e.g. java)

More information about this process id can be shown using the -o options flag. For a list, see this documentation page.

Here's one example that tells you a particular process PID's full command with arguments, user, group and memory usage (note how the multiple -o flags each take a pair, and how the command outputs with lots of whitespace padding):

ps -p $PID -o pid,vsz=MEMORY -o user,group=GROUP -o comm,args=ARGS 

Tip: for human-read output in the console, make args the last option - it'll usually be the longest and might get cut short otherwise.

Answer 2

Just type this and you will get what you want. Replace 'type_PID_here' with the PID.

cat /proc/type_PID_here/status