pbzip2: parallel bzipping

Probably this software existed for a quite long time but I didn’t know its existence ’til now: pbzip2
it’s basically a bzip2 algorithm implementation with pthreads support. This mean, in a always more SMP world, that you can greatly improve your bzipping perfomances (divide the zipping time by the number of cores you have et voilĂ !)

Compression syntax is totally compatible:

$ pbzip2 big.file

while to unzip you have to do

$ pbzip2 -d big.file.bz2

Use with caution (or with -l and -p switches) cause you can easily saturate your 4xSix-cores monster.

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.forward and /dev/null

Just a quick tip for you out there and a reminder for me. If you are using .forward files with your MTA (so, real users, not virtuals) and you want to discard everything received by that user, just put in his/her .forward


"|cat > /dev/null"

Remember that the quotes, they are mandatory (if you’re copy’n’pasting this, change the quotes because WordPress loves to change things)

Cron and multiple recipients

If you are using a maintainance user executing scheduled cronjobs, maybe you’ve found yourself needing to report the result of these jobs to different email addresses. Everyone knows for sure the MAILTO parameter, as explained in the crontab(5) manpages.

But maybe you don’t know that MAILTO is interpreted sequencially, when it’s found, so you can have different recipients in the same crontab, like in this example:


MAILTO="user1@domain.tld"
* * * * * echo "abc"

MAILTO=”user2@domain.tld”
* * * * * echo “dfe”

so user1 will get mailed with “abc” and user2 with “dfe”.
It works in the standard “cron” program, so for example you can use this tip in Debian or FreeBSD (and in other Unices to, I guess)