bg - Runs jobs in the background
The C shell has a built-in version of the bg command. If you are
using the C shell, and want to guarantee that you are using the com-
mand described here, you must specify the full path /usr/bin/bg. See
the csh(1) reference page for a description of the built-in command.
Interfaces documented on this reference page conform to industry standards
Refer to the standards(5) reference page for more information about indus-
try standards and associated tags.
Specifies the job to be resumed as a background job. If no job_id
operand is given, the most recently suspended job is used. The format
of job_id is described in the Jobs section of the ksh(1) reference
If job control is enabled (see the description of set -m in the ksh(1)
reference page), the bg utility resumes suspended jobs from the current
environment by running them as background jobs. If the job specified by
job_id is a job already running in the background, the bg utility has no
effect and will exit successfully.
Using bg to place a job into the background causes its process ID to become
"known in the current shell execution environment", as if it had been
started as an asynchronous list. See the Jobs section of the ksh(1) refer-
1. If job control is disabled, the bg utility exits with an error and no
job is placed in the background.
2. The bg utility does not work as expected when it is operating in its
own utility execution environment because that environment has no
The following exit values are returned:
0 Successful completion.
>>0 An error occurred.
The following environment variables affect the execution of bg:
Provides a default value for the internationalization variables that
are unset or null. If LANG is unset or null, the corresponding value
from the default locale is used. If any of the internationalization
variables contain an invalid setting, the utility behaves as if none of
the variables had been defined.
If set to a non-empty string value, overrides the values of all the
other internationalization variables.
Determines the locale for the interpretation of sequences of bytes of
text data as characters (for example, single-byte as opposed to multi-
byte characters in arguments).
Determines the locale used to affect the format and contents of diag-
nostic messages written to standard error.
Determines the location of message catalogues for the processing of
Commands: csh(1), fg(1), jobs(1), kill(1), ksh(1), Bourne shell sh(1b),
POSIX shell sh(1p), wait(1)