GNU Mcron

This is GNU Mcron, a tool to run jobs at scheduled times. It is a complete replacement for Vixie cron. Besides supporting the traditional Vixie syntax for its configuration files, GNU Mcron offers the possibility to define jobs using the Scheme language.

See the INSTALL file for generic information about how to configure and install GNU Mcron. If this file is not present, see HACKING for preliminary build instructions.

IMPORTANT NOTICES

Do not (yet) install this software on a machine which relies for its functioning on its current set of crontabs.

To not replace the cron daemon on a system, the package must be installed with the --disable-multi-user configure option.

Before installing this package for the first time, it is necessary to terminate any running cron daemons on your system. If your old cron is not Vixie or accurately Vixie compatible (files in /var/cron/tabs*, /var/cron/allow, /var/cron/deny, /etc/crontab, /var/run/cron.pid) then you will need to clear out all old crontabs and make new ones afresh - or else look very carefully at the options you pass to the package configure script, as follows.

It is often the case that GNU/Linux distributions and other Unices hacked the cron daemon to use different directories to those above. You can use configure options --spool-dir, --socket-file, --allow-file, --deny-file, --pid-file and --tmp-dir to make mcron behave similarly. Note that, with the exception of tmp-dir, none of these files or directories should be accessible by ordinary (non-root) users.

If your old cron is Vixie, or very similar, mcron should fall right into place where your old cron was (the binaries cron and crontab will be replaced, but if your existing system has a binary called crond, you should make this a link to mcron), and you should be able to continue to use your existing crontabs without noticing any changes.

If you don't want to clobber your existing cron executables, you can specify the --program-prefix option to configure with a prefix ending in a non-alphabetic character, for example "m.", and then run the programs as m.mcron, m.cron (or m.crond) and m.crontab.

After installation, read the info file for full instructions for use (typing 'info mcron' at the command line should suffice). Notes for end users, sysadmins, and developers who wish to incorporate mcron into their own programs are included here.

Features which might be implemented sometime sooner or later are noted in the TODO file.

Please send all bug reports to bug-mcron@gnu.org.

Mcron is free software. See the file COPYING for copying conditions.

The mcron development home page is at https://rdmp.org/dmbcs/mcron and the latest version can be obtained from https://rdmp.org/dmbcs/mcron.git.

The GNU home page for the project is http://www.gnu.org/software/mcron.

Copying and distribution of this file, with or without modification, are permitted in any medium without royalty provided the copyright notice and this notice are preserved. This file is offered as-is, without warranty of any kind.