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Asked: 2017-12-06 23:34:41 +0800 CST

jobs command not working. whereis jobs?

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I tried to test "jobs" command on Ubuntu 16.04. It seems that there is no "jobs" command on my system. I did what I learned like "whereis jobs", "whatis jobs", "which jobs", but Ubuntu replies "jobs:", "jobs: nothing appropriate", "", respectively. I also tried "sudo apt-get install jobs". Not successful. What should I do to make jobs command working on my Ubuntu 16.04 system. Thanks for reading.

background

2 Answers

  1. You can only use "jobs" if your shell has processes running in background (either using ctrl+z or by ampersand [&] sign after the command. i.e. top &). the command "jobs" shows nothing if your shell has no corresponding background processes running.

    "jobs" will show you the "full" command that is running as well as the job number. You may also use the "ps" command to see shell's jobs running in the background along with their PIDs. "ps" command shows only the command keyword that is running (not the parameters) nor the job number (only PID). You can't usually distinction foreground and background process with "ps" command because it shows you all processes running with your current active shell.

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  2. According to the manual, the monitor option is "on by default for interactive shells on systems that support it".

    set -m      Monitor mode.  Job control is enabled.  This option is
                           on by default for interactive shells on systems that
                           support it (see JOB CONTROL above).  All processes run
                           in a separate process group.  When a background job
                           completes, the shell prints a line containing its exit
                           status.

    To see if it's on, type set -o and look for the monitor line. If it is set to off, job control is disabled. Try typing set -m (or set -o monitor) to enable it. If that doesn't work, maybe your system doesn't support background jobs.

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