quick example that downloads some videos from youtube (CS106B Programming Abstraction) then renames the files using regex in zsh for file names ($match). Really cool and useful!

zsh-regex-file-rename-example.sh

# $match example for zsh
# inspiration:
# https://stackoverflow.com/questions/13043344/search-and-replace-in-bash-using-regular-expressions

# reprex

mkdir CS106B
cd CS106B

# download mp4s of programmming abstraction
youtube-dl -f mp4 "https://www.youtube.com/watch?v=kMzH3tfP6f8&list=PLFE6E58F856038C69"

# use reprex to chop off all the random garbage after download e.g.
# "Lecture 1 _ Programming Abstractions (Stanford)-kMzH3tfP6f8.mp4"
# vs
# "Lecture 1.mp4"

# $match matches the full regex then use ${match[1]} akin to using \\1 in perl or R (first set of parens)
for f in *
do
  re='(Lecture [0-9]+) (.*)'
  if [[ $f =~ $re ]];
  then
    mv "./$match" "./${match[1]}.mp4"
  fi
done


# rename again, but now we add a "0" infront of any single digit e.g.
# Lecture 1.mp4 -> Lecture 01.mp4
for f in *
do
  re='(Lecture ([0-9]).mp4$)'
  if [[ $f =~ $re ]];
  then
    mv "./$match[1]" "./Lecture 0${match[2]}.mp4"
  fi
done