UNIX for Dummies Questions & Answers

ls | while read name
do
  ext=${name##*.}
  first=${name%.*}
  pre=${first%%_*}
  nr=${first##*_}
  newnr=$(printf "%03d" $((nr-214)))
  mv "$name" "${pre}_${newnr}.${ext}"
done

for file_name in * ; do
to_file=`awk -F"[_.]" '{printf "%s_%03d.%s",$1,$2-214,$3}' $file_name`
mv $file_name $to_file
done

ls | while read name
do
  ext=${name##*.}
  first=${name%.*}
  pre=${first%%[0-9]*}
  nr=${first##*[^0-9]}
  newnr=$(printf "%03d" $((nr-214)))
  mv "$name" "${pre}${newnr}.${ext}"
done

ls | while read name                    
do
  ext=${name##*.}                      # ext becomes everything after the last dot
  first=${name%.*}                     # first becomes everything before the last dot
  pre=${first%%[0-9]*}                 # pre becomes every non-digit from the start (using the variable first)
  nr=${first##*[^0-9]}                 # nr becomes everything from the first digit until the end (using the variable first)
  newnr=$(printf "%03d" $((nr-214)))   # newnr becomes nr minus 214 and preambled with 0's so that it is always 3 digits.
  mv "$name" "${pre}${newnr}.${ext}"
done