Rename all files in a directory
named " S13E01-SeriesXY.avi" or " s13e01_blah.mp4" to 13x01-SeriesXY.mp4
for a in $(ls .); do
B=$(echo $a|sed s/[sS]13[eE]/13x/g)
mv $a $B
done
for a in $(ls .); do
B=$(echo $a|sed s/[sS]13[eE]/13x/g)
mv $a $B
done