# CRONTAB(1), CRON(8), ANACRONTAB(5), ANACRON(8): numbers and andanacron USE flag?

According to wiki.gentoo, cronie is a fork of vixie-cron done by Fedora. Additionally cronie comes with an anacron implementation which must be enabled through the anacron USE flag. https://wiki.gentoo.org/wiki/Cron The man pages do not mention "anacron USE flag", what is it?

The manpages mention CRONTAB(1), CRON(8), ANACRONTAB(5), ANACRON(8). What is the meaning of numbers (1), (5), and (8)?

Fedora22 comes with cronie and it's man pages already installed:

$rpm -q cronie cronie-anacron cron cronie-1.4.12-5.fc22.x86_64 cronie-anacron-1.4.12-5.fc22.x86_64 package cron is not installed$ man cronie
No manual entry for cronie

$man crontab CRONTAB(1) ...$ man cron
CRON(8)
...
cronie                                    2013-09-26                                   CRON(8)

$man anacrontab ANACRONTAB(5) ...$ man anacron
ANACRON(8)
...

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The numbers are the sections of the manual. To explore the different sections, you can read each one's intro page.

From a terminal, you can pass the section number to man like so: to read the manual page cron(8), you type: man 8 cron

In Gnome Help, to read a manual page, you hit Control+L and enter the optional section number after a dot, like: man:cron.8

So, cron(8) is in section 8 of the manual; man:intro.8 shows me:

Section 8 of the manual describes commands which either can be or are used only by the superuser, like system-administration commands, dae- mons, and hardware-related commands. As with the commands in described Section 1, the commands described in this section terminate with an exit status that indicates whether the command succeeded or failed. See intro(1) for more information.

This is important because sometimes things have the same name; eg apropos crontab shows me:

anacrontab (5)       - configuration file for Anacron
crontab (1)          - maintains crontab files for individual users
crontab (1p)         - schedule periodic background work
crontab (5)          - files used to schedule the execution of programs
crontabs (4)         - configuration and scripts for running periodical jobs
incrontab (1)        - table manipulator for inotify cron (incron)
incrontab (5)        - tables for driving inotify cron (incron)


If I want to read about the crontab files, I have to supply the manual section.

Note the distinction between sections 1 and 1p on their intro pages, also. crontab (1p) tells me what POSIX requires; crontab (1) tells what GNU+Linux actually provides, which is often a lot more interesting for day-to-day use (but the POSIX minimum is needed if you're trying to be portable to, say, MacOS as well.)

more

In addition, the USE flag is something used in Gentoo package management: Gentoo Portage. Read about Gentoo here.

( 2015-07-29 12:47:20 -0500 )edit

@BRPocock, thank you for the thorough answer.

( 2015-07-30 04:29:08 -0500 )edit