apt-get changelog

Manually for each package:
aptitude changelog package-name

Automatically for each upgrade (and of course also manually):
sudo apt-get install apt-listchanges
sudo dpkg-reconfigure apt-listchanges

crop and rescale without blur

see examples here.

convert input.png -crop 128x128+571+569 +repage -scale 1024x1024 output.png

With geometry argument as described here.
(width x height +offset_x +offset_y)

The positions of the filenames are important!

rename mp3 files using track number

for id3v2 tags:

for i in *.mp3; do num=`id3v2 --list "$i" | grep TRCK | cut -f 2 -d:`; mv "$i" "`printf %02d $num` - $i"; done