Bg built-in

The bg built-in resumes suspended jobs in the background.

Synopsis

bg [job_id…]

Description

See Job control for an overview of job control in yash-rs. The built-in resumes the specified jobs by sending the SIGCONT signal to them.

The (last) resumed job’s process ID is set to the ! special parameter.

Options

None.

Operands

Operands specify jobs to resume as job IDs. If omitted, the built-in resumes the current job.

Standard output

The built-in writes the job number and name of each resumed job to the standard output.

Errors

It is an error if:

• the specified job is not found,
• the specified job is not job-controlled, that is, job control was off when the job was started, or
• job control is off in the current shell environment.

Exit status

Zero unless an error occurs.

Examples

See Job control.

Compatibility

Many implementations allow omitting the leading % from job IDs, though it is not required by POSIX. Previous versions of yash allowed it, but this is not yet supported in yash-rs.

Some implementations (including the previous version of yash, but not this version) regard it is an error to resume a job that has already terminated.