Subj : Re: Cron
To   : Al
From : hal
Date : Mon Mar 08 2021 03:14 pm

 Al>  ac> Sourcing /etc/profile should also work but it would include other stu
 Al>  ac> that might not be needed. And sourcing a bash_profile from the home 
 Al> Sourcing your own .bash_profile (if you have one, I don't) will result
 Al> in cron having the usual user environment, if that is what you want.

Ahh the old question .bashrc or .bash_profile (but not quite)

OUTSIDE OF CRON ...
..bash_profile is used for login shells. .bashrc is used for shells that are
both interactive and non-login 

Cron should run in a non-login shell but it is also non-interactive and
therefore bash ignores both of these startup files

The bash(1) manpage puts it 
 /etc/profile      system wide execution for login shells
 ~/.bash_profile   personal initialization for login shells 
                   (initialized once per terminal)
 ~/.bashrc         individual PER interactive shell 
                   (initialized on every sub shell as well)

INSIDE CRON ...

Cron ignores ALL startup scripts. Period. So adding stuff in the normal places
won't work.

The normal recommendations are to

(1) rather than put a command on the command line of the crontab entry but
put a script and ensure that the script declares exactly what it needs to run
correctly. 
    This has the advantage over (2) in that if you mess around with your
..bash_profile or .bashrc and you are sourcing that then your batch jobs are
not messed up (which are usually much more important).

(2) place the settings in .bash_profile or .bashrc and then source them. This
ends up outputting potentially a lot into the cron logs that don't need to be
there. In addition the more commands and settings you have in your startup
scripts the more chance of messing up what should be a simple script.

(3) put the settings in a seperate file and source that. But then why bother
just place it in the script itself.

Most experienced system admins would opt for (1) with explicit exports for
every variable needed. At least that way the script is self contained and you
are not contaminating your startup files with stuff that is only used in a
one off script.

--- Mystic BBS v1.12 A46 2020/08/26 (Raspberry Pi/32)
 * Origin: Tribe BBS (21:1/177)

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