/dev/blog

I already wrote about sending mails with ssmtp, a simple alternative to sendmail. But since I got a few questions (and I tend to forget myself) how to use ssmtp’s revaliases-file, here is a short reminder:

/etc/revaliases, allows you to map a local user to a specific ‘From:’ address on outbound mail and to route that mail through a specific mailhub. But it will not rewrite the ‘To:’ address according to the local user who should receive the mail.

Usually, you would add aliases to /etc/aliases to ensure that a local user (receiving a mail) is mapped to a valid eMail address. But as the documentation clearly says (if you actually read it), ssmtp does not use /etc/aliases.

The solution turns out to be letting mail handle the alias – which is done by configuring aliases in /etc/mail.rc

set ask askcc append dot save crt
ignore Received Message-Id Resent-Message-Id Status Mail-From Return-Path Via Delivered-To
alias root root<yourname@domain.com>
alias localuser localuser<yourname@domain.com>

You can test it with with:

# echo test | mail -s "testing ssmtp" localuser

The mail will actually be delivered to yourname@domain.com (since ‘localuser’ is mapped to this address in /etc/mail.rc).

Enjoy!

Resources:
http://www.linux.com/archive/feature/132006
http://greybeardedgeek.net/?p=17

Well, there is no native command (at least, afaik), but you can use find to easily identify empty folders (which maybe helpful for maintenance, etc.):

# find /path -type d -empty

Find empty folder and list

# find /path -type d -empty -exec ls -ld {} \;

Find empty folder and save as temporary file

# find /path -type d -empty -exec ls -ld >> /tmp/savefiles.txt {} \;

Find empty folder and delete

# find /path -type d -empty -exec rmdir {} \;

See also find manpage