Misc scripts
Renaming daily/weekly/monthly rsnapshot folders
If something went wrong with rsnapshot, it might be neccessary to remove the last created backup folder. But then you'd have to rename the whole lots again, so that the new last one is called 0. For instance, you have 29 daily backups and remove daily.0. This command will rename 1 to 0, 2 to 1, 3 to 2, etc:
for i in `seq 1 29`; do mv daily.$i daily.`expr $i - 1`; done
Removing old kernels and headers
Because you automatically upgrade your kernels, your VMs get clogged up with old kernels and headers, which can eventually fill up your disk (space wise or inode wise). This is the way to remove all but the running kernel:
visser@cajones:~$ sudo apt-get purge `apt-show-versions | cut -d":" -f 1 | grep -E 'linux-(headers|image(-extra)?)-[0-9]+' | grep -v $(uname -r | sed -E 's/-[a-z]+$//')`
Removing set of e-mail address from another set of email address
List of address with optional names, separated by whitespace:
visser@rasputin:~$ cat addresses.txt dick@TIENHUIS.nl Dick Visser dnmvisser@Gmail.CoM Dick "Gmail" Visser dnmvisser@yahoo.com dick.visser@geant.org Dick Visser visser@terena.org Dick's old address...
Similar for a blacklist:
visser@rasputin:~$ cat blacklist.txt Dnmvisser@gmail.com Evil guy
You can 'subtract' the blacklist using this Ruby one line:
visser@rasputin:~$ ruby -e 'a = File.readlines("addresses.txt").map { |x| x.split.first.downcase } - File.readlines("blacklist.txt").map { |x| x.split.first.downcase }; puts a' dick@tienhuis.nl dnmvisser@yahoo.com dick.visser@geant.org visser@terena.org