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BATCH(1P) POSIX Programmer's Manual BATCH(1P)

PROLOG
This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (con-
sult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on
Linux.

NAME
batch - schedule commands to be executed in a batch queue

SYNOPSIS
batch

DESCRIPTION
The batch utility shall read commands from standard input and schedule them for execution in a batch queue. It shall be
the equivalent of the command:

at -q b -m now

where queue b is a special at queue, specifically for batch jobs. Batch jobs shall be submitted to the batch queue with
no time constraints and shall be run by the system using algorithms, based on unspecified factors, that may vary with
each invocation of batch.

Users shall be permitted to use batch if their name appears in the file /usr/lib/cron/at.allow. If that file does not
exist, the file /usr/lib/cron/at.deny shall be checked to determine whether the user shall be denied access to batch. If
neither file exists, only a process with the appropriate privileges shall be allowed to submit a job. If only at.deny
exists and is empty, global usage shall be permitted. The at.allow and at.deny files shall consist of one user name per
line.

OPTIONS
None.

OPERANDS
None.

STDIN
The standard input shall be a text file consisting of commands acceptable to the shell command language described in
Shell Command Language .

INPUT FILES
The text files /usr/lib/cron/at.allow and /usr/lib/cron/at.deny shall contain zero or more user names, one per line, of
users who are, respectively, authorized or denied access to the at and batch utilities.

ENVIRONMENT VARIABLES
The following environment variables shall affect the execution of batch:

LANG Provide a default value for the internationalization variables that are unset or null. (See the Base Definitions
volume of IEEE Std 1003.1-2001, Section 8.2, Internationalization Variables for the precedence of international-
ization variables used to determine the values of locale categories.)

LC_ALL If set to a non-empty string value, override the values of all the other internationalization variables.

LC_CTYPE
Determine 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 and input files).

LC_MESSAGES
Determine the locale that should be used to affect the format and contents of diagnostic messages written to stan-
dard error and informative messages written to standard output.

LC_TIME
Determine the format and contents for date and time strings written by batch.

NLSPATH
Determine the location of message catalogs for the processing of LC_MESSAGES .

SHELL Determine the name of a command interpreter to be used to invoke the at-job. If the variable is unset or null, sh
shall be used. If it is set to a value other than a name for sh, the implementation shall do one of the follow-
ing: use that shell; use sh; use the login shell from the user database; any of the preceding accompanied by a
warning diagnostic about which was chosen.

TZ Determine the timezone. The job shall be submitted for execution at the time specified by timespec or -t time rel-
ative to the timezone specified by the TZ variable. If timespec specifies a timezone, it overrides TZ. If time-
spec does not specify a timezone and TZ is unset or null, an unspecified default timezone shall be used.

ASYNCHRONOUS EVENTS
Default.

STDOUT
When standard input is a terminal, prompts of unspecified format for each line of the user input described in the STDIN
section may be written to standard output.

STDERR
The following shall be written to standard error when a job has been successfully submitted:

"job %s at %s\n", at_job_id, <date>

where date shall be equivalent in format to the output of:

date +"%a %b %e %T %Y"

The date and time written shall be adjusted so that they appear in the timezone of the user (as determined by the TZ
variable).

Neither this, nor warning messages concerning the selection of the command interpreter, are considered a diagnostic that
changes the exit status.

Diagnostic messages, if any, shall be written to standard error.

OUTPUT FILES
None.

EXTENDED DESCRIPTION
None.

EXIT STATUS
The following exit values shall be returned:

0 Successful completion.

>0 An error occurred.

CONSEQUENCES OF ERRORS
The job shall not be scheduled.

The following sections are informative.

APPLICATION USAGE
It may be useful to redirect standard output within the specified commands.

EXAMPLES
1. This sequence can be used at a terminal:

batch
sort < file >outfile
EOT

2. This sequence, which demonstrates redirecting standard error to a pipe, is useful in a command procedure (the
sequence of output redirection specifications is significant):

batch <<
! diff file1 file2 2>&1 >outfile | mailx mygroup
!

RATIONALE
Early proposals described batch in a manner totally separated from at, even though the historical model treated it almost
as a synonym for at -qb. A number of features were added to list and control batch work separately from those in at. Upon
further reflection, it was decided that the benefit of this did not merit the change to the historical interface.

The -m option was included on the equivalent at command because it is historical practice to mail results to the submit-
ter, even if all job-produced output is redirected. As explained in the RATIONALE for at, the now keyword submits the job
for immediate execution (after scheduling delays), despite some historical systems where at now would have been consid-
ered an error.

FUTURE DIRECTIONS
None.