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

background-processbitnamilinuxnode.jsnohup

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?

Best Answer

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.

Related Solutions

Linux – Process running in background got killed in linux

I would suggest that although '&' runs the command in background, when you exit your terminal it is still getting sent SIGHUP. You could use the disown command

disown prevents the current shell from sending a HUP signal to each of the given jobs when the current shell terminates a login session.

If job is omitted, the most recently started or stopped background job is used.

Linux – nohup multiple sequential commands

Easiest solution: Create a shell script with

 #/bin/sh
 tar -zcf archive.tar.gz.tmp mydir
 mv archive.tar.gz.tmp archive.tar.gz

And use nohup myscript. Possibly with some extra documentation in the script.

(Yes, I am a sucker for documentation. Especially when working with multiple people or when you might someday leave the job and your successor needs to figure out why".)

An alternative might be to start a new shell for a subtask (in this case your tar and move)

nohup `$(tar -zcf archive.tar.gz.tmp mydir; mv archive.tar.gz.tmp archive.tar.gz)

Alternative 2:

nohup ```tar -zcf archive.tar.gz.tmp mydir ; mv archive.tar.gz.tmp archive.tar.gz```.

I really prefer the script though. The comments in it might be quite useful when you or someone else looks at he script in a few years and wonders why it was done this way.

On a unrelated note: How the heck do I post an anser with a backtick in it? (The command for a shell to 'use this command ; feed the output to another command as input`).

Best Answer

Related Solutions

Linux – Process running in background got killed in linux

Linux – nohup multiple sequential commands

Related Topic