Originally published July 13, 2016 @ 10:18 am
This is a common question: how can I run nohup without creating the annoying nohup.out ? And the common answer is: you can’t. But this is not exactly true.
Some people have a dreadful habit of starting their applications using nohup with debug sent to stdout. The nohup.out will never be “rotated”, unlike a log file. It will keep growing until it consumes all available space. Even if you delete it or empty it out, the filesystem space will not be released, until the process wring to the file is terminated.
And so without further ado, lo and behold: running nohup without creating nohup.out:
nohup your_command </dev/null >/dev/null 2>&1 &
And here’s a little example. First, I rsync /etc to /etc_mirror using nohup to keep it running in the background:
[root@ncc1701 tmp]# mkdir /etc_mirror [root@ncc1701 tmp]# nohup rsync -av /etc/ /etc_mirror/ & [2] 56919 [root@ncc1701 tmp]# nohup: ignoring input and appending output to `nohup.out' [root@ncc1701 tmp]# [root@ncc1701 tmp]# [2]- Done nohup rsync -av /etc/ /etc_mirror/ [root@ncc1701 tmp]# du -sh /etc /etc_mirror 118M /etc 118M /etc_mirror [root@ncc1701 tmp]# wc -l nohup.out 3565 nohup.out [root@ncc1701 tmp]# rm nohup.out [root@ncc1701 tmp]# rm -r /etc_mirror
Here I repeat the same process with the </dev/null addition:
[root@ncc1701 tmp]# mkdir /etc_mirror [root@ncc1701 tmp]# nohup rsync -av /etc/ /etc_mirror/ </dev/null >/dev/null 2>&1 & [2] 61837 [root@ncc1701 tmp]# [root@ncc1701 tmp]# [2]- Done nohup rsync -av /etc/ /etc_mirror/ < /dev/null > /dev/null 2>&1 [root@ncc1701 tmp]# du -sh /etc /etc_mirror 118M /etc 118M /etc_mirror [root@ncc1701 tmp]# wc -l nohup.out wc: nohup.out: No such file or directory [root@ncc1701 tmp]# rm -r /etc_mirror
Hooray.
Experienced Unix/Linux System Administrator with 20-year background in Systems Analysis, Problem Resolution and Engineering Application Support in a large distributed Unix and Windows server environment. Strong problem determination skills. Good knowledge of networking, remote diagnostic techniques, firewalls and network security. Extensive experience with engineering application and database servers, high-availability systems, high-performance computing clusters, and process automation.
