BATCH(1POSIX)

📦 version 2017a, in debian bookworm, debian trixie, ubuntu jammy, ubuntu noble, ubuntu resolute, ubuntu stonking

💖 BATCH(1POSIX) — bestie, it's the POSIX Programmer's Manual 💖

okay so before we even get into it, heads up: this page is part of the POSIX Programmer's Manual (yes that's the manual name, and yes it's giving official). But the Linux implementation of this interface may differ, so pls consult the corresponding Linux manual page for details on Linux behavior. also maybe the interface just... isn't implemented on Linux at all?? 🙈 no cap. go check.

✨ PROLOG ✨

This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult 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

like, you hand it a lil to-do list and the system runs it when it feels like it. lowkey iconic.

🦋 SYNOPSIS 🦋

batch

that's it. that's the whole vibe. no flags. no operands. just vibes and stdin. 💅

🌸 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.

so real talk: the system decides when. unspecified factors. mystery algorithms. it's giving ✨chaos✨ but it's the spec's chaos so we respect it.

Users shall be permitted to use batch if their name appears in the file at.allow which is located in an implementation-defined directory. If that file does not exist, the file at.deny, which is located in an implementation-defined directory, shall be checked to determine whether the user shall be denied access to batch. If neither file exists, only a process with 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.

tl;dr on the guest list: at.allow is the VIP list, at.deny is the block list, and if neither exists you better have appropriate privileges or it's a no from the bouncer. 💀

💅 OPTIONS 💅

None.

(not a single flag. she's minimal. she's unbothered. she's booked and busy.)

🫶 OPERANDS 🫶

None.

💖 STDIN 💖

The standard input shall be a text file consisting of commands acceptable to the shell command language described in Chapter 2, Shell Command Language.

so like, actual shell commands. write them like you mean them.

🍓 INPUT FILES 🍓

The text files at.allow and at.deny, which are located in an implementation-defined directory, 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 POSIX.1‐2017, Section 8.2, Internationalization Variables 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 implementation 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 timezone and TZ is unset or null, an unspecified default timezone shall be used.

the SHELL situation is so unserious bestie, the implementation literally gets to pick and might just tell you which one it picked. mystery shell reveal 🎁

⭐ 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.

(unspecified format = she's mysterious, she's coy, she's a prompt you cannot predict 💅)

👑 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.

important!!! that cute "job 3 at Mon Sep 1 12:00:00 2025" message is NOT a diagnostic and does NOT change your exit status. same for the shell-picking warning. don't let them gaslight you.

💜 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.

read that again. if it errors, your job does not get queued. it's not late, it's not pending, it simply never happens. stay safe out there.

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
  1. 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
!

note the little warning in example 2: the sequence of those redirection specs is significant. 2>&1 >outfile is NOT the same as >outfile 2>&1. the order ate, and the order matters. 👑

💅 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 scheduling delays), despite some historical systems where at now would have been considered an error.

so basically: they thought about giving batch her own whole separate thing and then went "nah, not worth breaking history" and kept the at -qb energy. respectful honestly. 🙌

🫶 FUTURE DIRECTIONS 🫶

None.

🌈 SEE ALSO 🌈

  • at
  • The Base Definitions volume of POSIX.1‐2017, Chapter 8, Environment Variables

Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 7, 2018 Edition, Copyright (C) 2018 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 .

Any typographical or formatting errors that appear in this page are most likely to have been introduced during the conversion of the source files to man page format. To report such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html .

and that's the whole page bestie!! brought to you by IEEE/The Open Group, dated 2017, filed under BATCH(1POSIX). go schedule something chaotic, ily, bye 💖✨🎀

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