Beyond Linux® From Scratch (systemd edition) - Version 8.4

Chapter 12. System Utilities

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-8.4 platform.

Package Information

at Dependencies

Required

An MTA

Optional

Linux-PAM-1.3.0

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 2019-02-17 18:19:58 -0800