at-3.1.23

#### Beyond Linux® From Scratch (systemd Edition) - Version 9.0

### Chapter 12. System Utilities

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# at-3.1.23

## Introduction to at

The at package provide delayed job execution and batch processing. It is required for Linux Standards Base (LSB) conformance.

This package is known to build and work properly using an LFS-9.0 platform.

### Package Information

- Download (HTTP): http://ftp.debian.org/debian/pool/main/a/at/at_3.1.23.orig.tar.gz

- Download MD5 sum: 1cec945506b5ddf1d776c92c315fc581

- Download size: 272 KB

- Estimated disk space required: 1.6 MB

- Estimated build time: less than 0.1 SBU

### at Dependencies

#### Required

An MTA

#### Optional

Linux-PAM-1.3.1

User Notes: http://wiki.linuxfromscratch.org/blfs/wiki/at

## Installation of at

Before building at, as the `root` user you should create the group and user `atd` which will run the atd daemon. Also ensure the working directory for the daemon exists:

    groupadd -g 17 atd                                                  &&
    useradd -d /dev/null -c "atd daemon" -g atd -s /bin/false -u 17 atd &&
    mkdir -p /var/spool/cron

Fix `Makefile.in` so that the documentation directory is installed in the specified docdir:

    sed -i '/docdir/s/=.*/= @docdir@/' Makefile.in

Regenerate the build files to be consistent with this package version:

    autoreconf

Install at with the following commands:

    ./configure --with-daemon_username=atd        \
                --with-daemon_groupname=atd       \
                SENDMAIL=/usr/sbin/sendmail       \
                --with-systemdsystemunitdir=/lib/systemd/system &&
    make -j1

This package does not come with a test suite.

Now, as the `root` user:

    make install docdir=/usr/share/doc/at-3.1.23 \
                 atdocdir=/usr/share/doc/at-3.1.23

## Configuring at

### Config Files

`/etc/at.allow` and `/etc/at.deny` determines who can submit jobs via at or batch.

### Systemd Unit

To start the atd daemon at boot, enable the previously installed systemd unit by running the following command as the `root` user:

    systemctl enable atd

## Contents

Installed Programs: at, atd, atq (symlink), atrm (symlink), atrun, and batch
Installed Libraries: None
Installed Directories: /var/spool/cron/at{jobs,spool} and /usr/share/doc/at-3.1.23

### Short Descriptions

at | queues, examines or deletes jobs for later execution.
atd | is the daemon that runs jobs queued for later execution.
atq | lists the user's pending jobs, or all jobs, if superuser.
atrm | deletes jobs, identified by their job number.
atrun | runs jobs queued for later execution.
batch | is a script that executes commands when system load levels permit.

Last updated on 2019-08-17 15:16:30 -0700

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