How to find out is a program run with nohup or not?

Question

There is no difference in ps -ef | grep sleep output to commands:

nohup sleep 60 &

sleep 60 &

In which way can I discover that program is run with nohup?

Solution

• You need to know pid of process you want to look at. You can use pgrep or jobs -l:

  jobs -l
  [1]-  3730 Running    sleep 1000 &
  [2]+  3734 Running    nohup sleep 1000 &
  

  Actually, this might already tell you the answer, unless you logged off and logged in again (then jobs -l will not show anything).

• Take a look at /proc/<pid>/fd. Processes started with nohup will list nohup.out files:

  mvp@linux:~$ ls -l /proc/3734/fd
  total 0
  l-wx------ 1 mvp mvp 64 Oct 29 02:32 0 -> /dev/null
  l-wx------ 1 mvp mvp 64 Oct 29 02:32 1 -> /home/mvp/nohup.out
  l-wx------ 1 mvp mvp 64 Oct 29 02:32 2 -> /home/mvp/nohup.out
  

  and started without nohup will not:

  mvp@linux:~$ ls -l /proc/3730/fd
  total 0
  lrwx------ 1 mvp mvp 64 Oct 29 02:28 0 -> /dev/pts/1
  lrwx------ 1 mvp mvp 64 Oct 29 02:28 1 -> /dev/pts/1
  lrwx------ 1 mvp mvp 64 Oct 29 02:28 2 -> /dev/pts/1