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bg(1)

NAME

bg - Runs jobs in the background

SYNOPSIS

bg [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 standards as follows: bg: XPG4, XPG4-UNIX Refer to the standards(5) reference page for more information about industry standards and associated tags.

OPTIONS

None

OPERANDS

job_id 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 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

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 suspended jobs.

EXIT STATUS

The following exit values are returned: 0 Successful completion. >0 An error occurred.

ENVIRONMENT VARIABLES

The following environment variables affect the execution of bg: LANG 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. LC_ALL If set to a non-empty string value, overrides the values of all the other internationalization variables. LC_CTYPE Determines the locale for the interpretation of sequences of bytes of text data as characters (for example, single-byte as opposed to multibyte characters in arguments). LC_MESSAGES Determines the locale used to affect the format and contents of diagnostic messages written to standard error. NLSPATH Determines the location of message catalogues for the processing 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)