The wait builtin command

Synopsis

wait [-f] [-n] [-p VARNAME] [ID...]

The wait builtin command is used to wait for job completion and return exit status.

if ID is a job specification, it waits for all processes in the pipeline of this job
waits for a specific job (asynchronous command) and report its exit status if one or more ID is given
waits for all running jobs (asynchronous commands)
waits for "the next" job (-n option)
waits for termination instead of status change (-f option)

ID may be an operating system process identifier or a shell job specification.

Option	Description
`-n`	Waits for "the next" child to exit (as opposed to "all children" without this option). Accepts a list of IDs (jobs)
`-f`	Waits for the termination of the given `ID` (instead of waiting for a status change only)
`-p VARNAME`	When waiting for a list (-n) or all jobs, writes the job ID to the job that was actually terminated into the variable `VARNAME`

The return status is the return status of the job waited for, or

Status	Reason
0	waited for all jobs in shell's job list
1	the given `ID` is not a valid job or process ID