Re: where are the crontab files in Trixie?

[Kushal Kumaran <kushal@locationd.net>]

On Tue, Feb 27 2024 at 10:15:59 AM, Gary Dale <gary@extremeground.com> wrote:
> I'm running Debian/Trixie on an AMD64 system. I have an old wifi
> adapter that Linux has problems with that works once I run:
>
> /usr/sbin/modprobe brcmfmac
> echo 13b1 0bdc > /sys/bus/usb/drivers/brcmfmac/new_id
>
> However when I add those lines to the root's crontab using # crontab -e as
>
> @reboot /usr/sbin/modprobe brcmfmac
> @reboot echo 13b1 0bdc > /sys/bus/usb/drivers/brcmfmac/new_id
>
> the second line fails. I get an e-mail stating "/bin/sh: 1: cannot
> create /sys/bus/usb/drivers/brcmfmac/new_id: Directory nonexistent"
>
> I'm not sure if the modprobe is working or if the module is being
> loaded without it. It's likely that debian detects the need for the
> module and loads it.
>

Is it possible that the command is being run before the module is
loaded.  Consider putting both into a single command, perhaps by writing
a script that does both things.

> Anyway, that got me down the rabbit hole to try to find where the
> crontab file is.
>
>  ls -l /root/cron*
> ls: cannot access '/root/cron*': No such file or directory
>
> also
>
> # whereis crontab
> crontab: /usr/bin/crontab /etc/crontab
> /usr/share/man/man1/crontab.1.gz /usr/share/man/man5/crontab.5.gz
>
> so it's not in the location that you'd expect. Nor can I find it in
> /etc/. The various cron files there don't contain the lines I;m
> looking for.
>

Editing/creating crontab files using "crontab -e" creates it in
/var/spool/cron/crontabs.

> <snipped crontab content>
>
> Can anyone explain how Trixie is handling crontabs now?

This behavior has existed forever.  I'm on bookworm, though, so no idea
if anything is changing in trixie.

-- 
regards,
kushal