What do slackers put in cron.*
 

I've just started looking into using cron, which I'm fairly new to linux. I've written a script to sync my time daily but was wondering what others use cron for?

Thanks

Usually for system maintenance tasks.

... and see man crontab for how to write an entry.

Note, you use crontab -e to edit a crontab file.

Hope this helps some.

What I have in my personal crontab:

1. remove vim/emacs backup files older than 30 days, once per day
2. get weather data from noaa for conky, twice per day
3. download any Slackware patches that exists twice a month

John

Avoiding Repetitive Tasks.

Member Response
 

Hi,

Or to run tasks on timely basis. :)

I use cron to run every six minutes the script that among the other things downloads new mail using POP3, checks whether new patches for Slackware appeared, and stores the ChangeLog.txt file locally.

I chmod 000 /etc/cron.daily/slocate to cut down on my disks' wear-and-tear, and run an analogous command by hand perhaps three times per year.

Like you, I add rsetdate to /etc/cron.daily. On my personal server in the colo I also added a script that downloads the Slackware changelog and emails any new entries to myself and some friends:
http://ciar.org/ttk/public/slacklog.pl

I run my podcatcher (I'm currently using podget) to pick my podcasts at 04:00 every morning.

Backup, update my custom motd, mail notification in case of alarm, and other things..

Thanks for your replies. @w1k0, I like the idea of checking for patches and maybe mailing them to root. Other ideas I had was to periodically run programs like aide and rkhunter, or would that be better done from a live distro?

Another thing I was thinking about was retrieving gmail, does anyone do this?

I have a script in cron.daily to sync my system clock with a time server.

Member Response
 

Hi,

'Time' is one that I do on a regular 'cron' task. Be sure to use a 'pool' so the load is handled properly.

I don't make much use of cron as I'm more of a ad-hoc kind of guy. Maybe if I left my system up 24x7 then I'd do things differently, but my box sleeps when I sleep.
:)


I think you're proably right to disable it. slocate/updatedb may make sense on a server with millions of files, but for a modern desktop/workstation that has more than enough ram to keep inodes/dirents in vfs_cache I'm not convinced a database based solution like slocate makes any sense..

I have this in my .bashrc, which I use instead and will pretty much do the same job as an "slocate -i" does without the need to run updatedb.

I mirror the host with rsync and sync the system time with sntp, both daily.

Yes! Your gmail is available via IMAP, and mbsync works quite nicely to retrieve it all.

This is my ~/.mbsyncrc, with some sekrit parts swapped out with "foo", "YOURGMAILPASSWORD", "YOURGMAILLOGIN", or "YOURNAME":

With this in place, the command "mbsync foo" pulls all of my gmail messages into ~/Maildir/

Come to think of it, putting this in /etc/cron.weekly seems like a pretty good idea. I will do that.

@ttk thanks for your example config file, I added my info onto mine but when I run mbsync foo it complains about /etc/pki/tls/certs/ca-bundle.crt no such file or directory. Is there a package I'm missing, or is there something I need to do to create it?

Ok, sorted the cert issue out but I'm having trouble with Maildir

Reading configuration file /home/me/.mbsyncrc
Resolving imap.gmail.com... ok
Connecting to 173.194.66.108:993... ok
Connection is now encrypted
Logging in...
Channel foo
Selecting slave INBOX... Maildir error: '/home/me/Maildir/' is no valid mailbox

Thanks.

I don't remember where I got mine, but looking at the comments in the file itself it appears to be derived from the mozilla sources:

I see a mozilla-1.9.2/security/nss/lib/ckfw/builtins/certdata.txt in a firefox source tarball, but it's not obvious to me how to extract ca-bundle.crt from certdata.txt.

Aha -- here's a script which claims to do it all for you. I haven't tested it, but see if it works for you:
http://www.floodgap.com/software/tty...-ca-bundle.txt

Alternatively, if you're feeling trusting, you could just download the file I've been using here:
http://ciar.org/ttk/public/ca-bundle.crt.txt

It's a bit picky about its Maildir format. This should work:
# mkdir -p /home/me/Maildir/cur /home/me/Maildir/new /home/me/Maildir/tmp
# chmod -R 700 /home/me/Maildir

Thanks ttk, that worked :) ... I got my ca-certificates.crt in /etc/ssl/certs/ and it seems to work fine, whether that's the correct thing to do. I'll have a look at your links though. What do you use to read your mail from your inbox?

"grep" and "less", mostly :-) I primarily use it for searching. But mutt reads from a Maildir quite nicely too.

You'll want to read this: http://www.elho.net/mutt/maildir/

Thanks once again ttk, everything seems to be working fine and mutt works great after that link you posted.

Cheers :)

Yay! :-) I'm glad it works for you.

I just added this as /etc/cron.weekly/archive-gmail.sh:

Triggering it manually (as root) appears to do the expected thing.

I use a cronjob to update a bash script every 5 mins that will echo to /etc/issue, so that when I open a terminal I see correct and updated values for HDD space, uptime, etc.

Among other things (backups, clean up tasks, etc.), I have a crontab entry to backup the crontab itself, just in case I screw it up, which has happened before.

Personally I don't know why anyone would use mbsync when Slackware comes with perfectly good copies of fetchmail and getmail, but I digress.

Personally I use cron to run getmail every minute for my user account. My root's crontab is mainly used to do my nightly backups using rsync. I use /etc/cron.daily for this. Since I don't really use my root's mailspool for anything but receiving system messages, I turn off root crontab's default configuration of directing all system output to /dev/null and make it only output STDOUT to /dev/null.

That way, if an error occurs with my backup, the root user will get an email notifying me of same.