bg command in Linux with Examples

In Linux, the bg command is a useful tool that allows you to manage and move processes between the foreground and background. It's especially helpful when you want to multitask in the terminal by placing a process in the background, enabling you to continue using the terminal for other commands while the process runs quietly in the background.

Example of bg Command in Linux

Step 1: Start a long-running process (e.g., sleep 60).

sleep 6

Step 2: Suspend the process by pressing Ctrl + Z.

Output:

[1]+  Stopped                 sleep 60

Step 3: Resume the suspended process in the background using bg.

bg

Output:

[1]+ sleep 60 &

• The process sleep 60 resumes execution in the background.
• You can verify it by running the jobs command:

Syntax

bg [job_spec ...]

where,

• job_spec: This is used to identify the job you want to move to the background. It can be specified in several formats:
• %n: Refers to job number n.
• %str: Refers to a job that was started by a command beginning with str.
• %?str: Refers to a job that was started by a command containing str.
• %% or %+: Refers to the current job. Both fg and bg commands will operate on this job if no job_spec is provided.
• %-: Refers to the previous job.

If no job_spec is provided, the most recent job is resumed in the background.

Useful Options for bg command

1. bg [JOB_SPEC]:

This command is used to put the mentioned job in background. In the below screenshot, we do following : 'sleep 500' is used to create dummy foreground job.

• We use jobs command to list all jobs
• We create a process using sleep command, we get its ID as 1.
• We put it in background by providing its ID to bg.

2. bg --help:

Displays the help information for the bg command. This is useful if you need more information on how to use the command or if you're unsure of the available options.