The program adopts one of three different personalities depending on the name used to invoke it. In a standard installation, the program is installed in the system under the names mcron, cron and crontab (installed SUID).
The recommended way to invoke the program is via the mcron personality described in the next section. The program can also be run as cron by root, and by the SUID program crontab by individual users to gain backwards compatibility with Vixie cron. However, due to the fact that this daemon process is shared by, and under control of, all the users of the system it is possible (though very unlikely) that it may become unusable, hence the recommendation to use the mcron personality.
Furthermore, the Vixie personality is considered deprecated by this author (it offers not a single advantage over the mcron personality, and bloats the code by a factor of three). It is unlikely that this personality will ever actually go away, but the program may in future be split into two distinct parts, and new developments will only take place in the part which implements the mcron personality.
|• Invoking mcron|
|• Invoking cron or crond|
|• Invoking crontab|
|• Behaviour on laptops|
|• Exit codes|