bg(1)bg(1)NAMEbg - Runs jobs in the background
SYNOPSISbg [job_id...]
Note
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 command
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.
STANDARDS
Interfaces documented on this reference page conform to industry stan‐
dards as follows:
bg: XCU5.0
Refer to the standards(5) reference page for more information about
industry standards and associated tags.
OPTIONS
None
OPERANDS
Specifies the job to be resumed as a background job. If no job_id oper‐
and 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 page.
DESCRIPTION
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) reference page.
RESTRICTIONS
If job control is disabled, the bg utility exits with an error and no
job is placed in the background. The bg utility does not work as
expected when it is operating in its own utility execution environment
because that environment has no suspended jobs.
EXIT STATUS
The following exit values are returned: Successful completion. An
error occurred.
ENVIRONMENT VARIABLES
The following environment variables affect the execution of bg: Pro‐
vides 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 vari‐
ables contain an invalid setting, the utility behaves as if none of the
variables had been defined. If set to a non-empty string value, over‐
rides 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 diagnostic messages written to standard
error. Determines the location of message catalogues for the process‐
ing of LC_MESSAGES.
SEE ALSO
Commands: csh(1), fg(1), jobs(1), kill(1), ksh(1), Bourne shell
sh(1b), POSIX shell sh(1p), wait(1)
Standards: standards(5)bg(1)
