BATCH(P) POSIX Programmer's Manual BATCH(P)NAMEbatch - schedule commands to be executed in a batch queue
SYNOPSISbatchDESCRIPTION
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 fac‐
tors, 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 permit‐
ted. 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 accept‐
able 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 utili‐
ties.
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 Vari‐
ables for the precedence of internationalization 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 standard 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 implemen‐
tation shall do one of the following: 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 relative to the
timezone specified by the TZ variable. If timespec specifies a
timezone, it overrides TZ . If timespec does not specify a time‐
zone 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 writ‐
ten 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 com‐
mand 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 com‐
mands.
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 re‐
direction 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 submitter, 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 schedul‐
ing delays), despite some historical systems where at now would have
been considered an error.
FUTURE DIRECTIONS
None.
SEE ALSO
at
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group. In the
event of any discrepancy between this version and the original IEEE and
The Open Group Standard, the original IEEE and The Open Group Standard
is the referee document. The original Standard can be obtained online
at http://www.opengroup.org/unix/online.html .
IEEE/The Open Group 2003 BATCH(P)
