jobs Command: Managing Background Processes
Summary
The jobs command provides a convenient way to list, monitor, and manage background processes in your current shell environment. It is useful for checking the status of processes you've sent to the background using & or Ctrl+Z followed by bg.
Introduction
The jobs command is a built-in shell command that displays a list of background jobs, their process IDs (PIDs), and their current status. This command is invaluable for users who frequently run long-running tasks in the background and need to keep track of their progress or manage them. It allows you to bring background processes to the foreground, stop them, or kill them.
Use Case and Examples
Listing all background jobs
This simple command lists all currently running or stopped background jobs associated with your current shell session.Listing jobs with more detail
This command provides a more detailed output, including the process ID (PID) of each job. This is helpful for using other commands likekill. Bringing a specific job to the foreground
This command brings job number 1 to the foreground. The% symbol indicates that you're referring to a job number. Replace 1 with the actual job number you want to bring to the foreground. Stopping a specific job
This command sends theSTOP signal to job number 1, effectively pausing its execution. You can then resume it later with bg %1 or bring it to the foreground with fg %1. Killing a specific job
This command sends theTERM signal to job number 1, requesting it to terminate. If the job doesn't terminate gracefully, you can use kill -9 %1 (sends SIGKILL) as a last resort, but be cautious as this forcefully terminates the process without allowing it to clean up. Commonly used flags
| Flag | Description | Example |
|---|---|---|
-l | Lists process IDs (PIDs) in addition to the normal output. | jobs -l |
-n | Lists only jobs that have changed status since the last notification. | jobs -n |
-p | Lists process IDs only, one PID per line. | jobs -p |
-r | Lists only running jobs. | jobs -r |
-s | Lists only stopped jobs. | jobs -s |