.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved 
.TH "BATCH" 1P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual"
.\" batch 
.SH NAME
batch \- schedule commands to be executed in a batch queue
.SH SYNOPSIS
.LP
\fB\fP \fIbatch\fP\fB\fP
.SH DESCRIPTION
.LP
The \fIbatch\fP utility shall read commands from standard input and
schedule them for execution in a batch queue. It shall be
the equivalent of the command:
.sp
.RS
.nf

\fBat -q b -m now
\fP
.fi
.RE
.LP
where queue \fIb\fP is a special \fIat\fP 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 \fIbatch\fP.
.LP
Users shall be permitted to use \fIbatch\fP if their name appears
in the file \fB/usr/lib/cron/at.allow\fP. If that file does not
exist, the file \fB/usr/lib/cron/at.deny\fP shall be checked to determine
whether the user shall be denied access to \fIbatch\fP.
If neither file exists, only a process with the appropriate privileges
shall be allowed to submit a job. If only \fBat.deny\fP
exists and is empty, global usage shall be permitted. The \fBat.allow\fP
and \fBat.deny\fP files shall consist of one user name
per line. 
.SH OPTIONS
.LP
None.
.SH OPERANDS
.LP
None.
.SH STDIN
.LP
The standard input shall be a text file consisting of commands acceptable
to the shell command language described in \fIShell Command Language\fP
\&.
.SH INPUT FILES
.LP
The text files \fB/usr/lib/cron/at.allow\fP and \fB/usr/lib/cron/at.deny\fP
shall contain zero or more user names, one per line,
of users who are, respectively, authorized or denied access to the
\fIat\fP and \fIbatch\fP
utilities. 
.SH ENVIRONMENT VARIABLES
.LP
The following environment variables shall affect the execution of
\fIbatch\fP:
.TP 7
\fILANG\fP
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 internationalization variables used to determine
the values of locale categories.)
.TP 7
\fILC_ALL\fP
If set to a non-empty string value, override the values of all the
other internationalization variables.
.TP 7
\fILC_CTYPE\fP
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).
.TP 7
\fILC_MESSAGES\fP
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.
.TP 7
\fILC_TIME\fP
Determine the format and contents for date and time strings written
by \fIbatch\fP.
.TP 7
\fINLSPATH\fP
Determine the location of message catalogs for the processing of \fILC_MESSAGES
\&.\fP 
.TP 7
\fISHELL\fP
Determine the name of a command interpreter to be used to invoke the
at-job. If the variable is unset or null, \fIsh\fP shall be used.
If it is set to a value other than a name for \fIsh\fP, the implementation
shall do one of the following: use that shell; use \fIsh\fP; use the
login shell from the user database; any of the preceding accompanied
by a warning
diagnostic about which was chosen.
.TP 7
\fITZ\fP
Determine the timezone. The job shall be submitted for execution at
the time specified by \fItimespec\fP or \fB-t\fP
\fItime\fP relative to the timezone specified by the \fITZ\fP variable.
If \fItimespec\fP specifies a timezone, it overrides
\fITZ .\fP If \fItimespec\fP does not specify a timezone and \fITZ\fP
is unset or null, an unspecified default timezone shall be
used.
.sp
.SH ASYNCHRONOUS EVENTS
.LP
Default.
.SH STDOUT
.LP
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.
.SH STDERR
.LP
The following shall be written to standard error when a job has been
successfully submitted:
.sp
.RS
.nf

\fB"job %s at %s\\n",\fP \fIat_job_id\fP\fB, <\fP\fIdate\fP\fB>
\fP
.fi
.RE
.LP
where \fIdate\fP shall be equivalent in format to the output of:
.sp
.RS
.nf

\fBdate +"%a %b %e %T %Y"
\fP
.fi
.RE
.LP
The date and time written shall be adjusted so that they appear in
the timezone of the user (as determined by the \fITZ\fP
variable).
.LP
Neither this, nor warning messages concerning the selection of the
command interpreter, are considered a diagnostic that changes
the exit status.
.LP
Diagnostic messages, if any, shall be written to standard error.
.SH OUTPUT FILES
.LP
None.
.SH EXTENDED DESCRIPTION
.LP
None.
.SH EXIT STATUS
.LP
The following exit values shall be returned:
.TP 7
\ 0
Successful completion.
.TP 7
>0
An error occurred.
.sp
.SH CONSEQUENCES OF ERRORS
.LP
The job shall not be scheduled.
.LP
\fIThe following sections are informative.\fP
.SH APPLICATION USAGE
.LP
It may be useful to redirect standard output within the specified
commands.
.SH EXAMPLES
.IP " 1." 4
This sequence can be used at a terminal:
.sp
.RS
.nf

\fBbatch
sort < file >outfile
EOT
\fP
.fi
.RE
.LP
.IP " 2." 4
This sequence, which demonstrates redirecting standard error to a
pipe, is useful in a command procedure (the sequence of output
redirection specifications is significant):
.sp
.RS
.nf

\fBbatch <<
! diff file1 file2 2>&1 >outfile | mailx mygroup
!
\fP
.fi
.RE
.LP
.SH RATIONALE
.LP
Early proposals described \fIbatch\fP in a manner totally separated
from \fIat\fP, even
though the historical model treated it almost as a synonym for \fIat\fP
\fB-qb\fP. A number of
features were added to list and control batch work separately from
those in \fIat\fP. Upon
further reflection, it was decided that the benefit of this did not
merit the change to the historical interface.
.LP
The \fB-m\fP option was included on the equivalent \fIat\fP 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 \fIat\fP, the \fBnow\fP keyword submits the job for immediate
execution (after scheduling
delays), despite some historical systems where \fIat\fP \fBnow\fP
would have been considered
an error.
.SH FUTURE DIRECTIONS
.LP
None.
.SH SEE ALSO
.LP
\fIat\fP
.SH 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 .