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nohup <command> <arg> &

When I SSH into a Linux server, if I want to run a command and make sure that it will continue to run in the background after I logout from SSH, I will use the above commands.

Recently I am using a server stack called Bitnami Node.js stack. It is a self-contained software bundle. There is a node binary in the bin folder in the installation directory.

In the command line, I am able to use the node command to run my JS programs: node <js_program.js>. There is no problem.

But, I would like to continue to run the program after I logout from SSH. When I run nohup <installation_dir>/nodejs/bin/node <js_program.js> > <stdout.out> &, the program will run in the background. But, when I logout from SSH, the program will also terminate immediately. It seems that the nohup command has no effect in this case.

How can I fix this issue?

userpal
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    Have you ever considered running your command via `screen` or `tmux`? – EEAA Apr 12 '16 at 15:00
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    What is the output of stdout.out and nohup.out? Is it showing anything as why its terminating? I guess it would be some kind of limitation in the infrastructure as Bitnami seems to be a stack dedicated to running Node apps, so maybe you don't have a fully working OS as you are expecting (just a guess) – Pablo Martinez Apr 12 '16 at 16:38

3 Answers3

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Running:

nohup command ... > file &

will leave stderr and stdin open. Instead, run:

nohup command ... > file 2>&1 <&- &

or:

nohup command ... > logfile 2> errfile <&- &

which will redirect stdout and close stdin.

Keep in mind that your command may abort if it can't read from stdin.

Derek Ludwig
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If you have the at package installed, and you're not denied (either directly via /etc/at.deny, or implicitly via /etc/at.allow) from using it, try using either of:

  echo "<installation_dir>/nodejs/bin/node <js_program.js> > <stdout.out>" | at now

or:

  at now

and specify your command at the at> prompt.

This should schedule the command to run immediately via the at daemon.

This how I've traditionally "emulated" nohup on systems with broken nohup implementations (AIX 5.3 and earlier, for example).

Christian Henry
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I managed to solve this problem by changing the way I logout from the SSH shell terminal.

Instead of clicking the X button to close the PuTTY window, I type exit in the SSH shell terminal to logout. Now the process is able to continue to run in the background after I logout.

If I click the X button to close the window, the background process will terminate immediately.

userpal
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