fg command in Linux with Examples

The fg command in Linux is used to bring a background job to the foreground. It allows you to interact with the process directly through the terminal.

• Resumes a background or stopped job in the foreground.
• Useful for switching back to a process that was sent to the background with bg 0r &.

Example:

Command:

sleep 60 &
fg %3

Syntax

fg [job_spec]

The job_spec is a way to refer to the background jobs that are currently running or suspended. Here are some common ways to specify a job:

• %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 (this is the default job operated on by fg if no job_spec is provided).
• %-: Refers to the previous job.

Key Options for the fg command

1. fg [JOB_SPEC]:

This is the primary use of the fg command, bringing a specified job running in the background back to the foreground. For example, if you create a dummy job using sleep 500, you can bring it back to the foreground by referencing its job number:"sleep 500" is a command which is used to create a dummy job which runs for 500 seconds.

2. fg --help:

This option displays help information for the fg command, explaining usage and available options.

Suggested Quiz

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4 Questions

What does the fg command do in Linux?

• A

  Starts a new job in the background

• B

  Stops a running job immediately

• C

  Brings a background job to the foreground

• D

  Deletes a running job

Explanation:

fg is used to move a background or stopped job back to the foreground.

Which fg syntax brings the job whose command starts with the text "sleep" to the foreground?

• A

  fg %sleep

• B

  fg %?sleep

• C

  fg sleep

• D

  fg %/sleep/

Explanation:

%str matches a job whose command begins with the specified text.

Which command brings job number 4 to the foreground?

• A

  fg job4

• B

  fg %4

• C

  fg 4&

• D

  fg @@4

Explanation:

%4 is the correct job specifier for job number 4.

A background job was started using the command "backup_data.sh". Which fg syntax correctly identifies the job using a pattern that matches any job containing the string "data"?

• A

  fg %data

  
  

• B

  fg %?data

• C

  fg %%data

• D

  fg backup_data.sh &

Explanation:

%?str matches a job whose command line contains the substring anywhere.

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