Question

I need help with the following:

I have these files with names: ABC.rt1, ABC.rt2, ... , ABC.rt8

I should rename all of them in the following way: if the number, let us say i at the end .rt${i} is odd, then replace the extension by appendig AB, else CD. For example I would expect these output:

ABC.rt1 –> ABC.rt1-AB

ABC.rt2 –> ABC.rt1-CD … etc.

I tried to use this simple script, but does not work:

for i in `seq 1 8`; do mv -v ./ABC.rt${i} ./ABC.rt${if [ $(( $i % 2 )) -eq 0 ] ; then echo ${i}-CD; else echo ${i}-AB;fi};done

Can you help me?

Answer 1

Try:

for i in `seq 1 8`; do
  if [ $(( $i % 2 )) -eq 0 ] ; then
    newext=${i}-CD
  else
    newext=${i}-AB
  fi
  mv -v ./ABC.rt${i} ./ABC.rt$newext
done

Don’t try and cram all that in a single line, it’s unreadable and your syntax ends up being incorrect.