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userpal
Asked: 2016-04-13 06:59:09 +0800 CST

How to use nohup to continue to run a command after the user logout?

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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?

linux background-process nohup node.js bitnami

3 Answers

  1. 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.

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  2. 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).

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  3. Best Answer

    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.

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