A quick, dirty, and likely dangerous bash function to rename files using a find-replace style regex with capture groups referenced as such: \1 \2 \3...n

mv_regex.sh

# source this file or copy and paste it into your ~/.bash_profile 

function mv_regex()
{
  regex="$1"
  replace="$2"
  FILE_LIST=()
  NEW_NAMES=()
  files="*"
  
  for f in $files
  do 
    if [[ $f =~ $regex ]]; then
      if [[ ${#BASH_REMATCH[@]} > 1 ]]; then
        let "var=0"
      
        for i in "${BASH_REMATCH[@]}"
        do
          target="\\$var"
          yarget="${BASH_REMATCH[$var]}"
          new_name="${replace//$target/$yarget}"
          let "var=var+1"
        done
      echo "$f --> $new_name"
      FILE_LIST+=("$f")
      NEW_NAMES+=("$new_name")
      fi  
    fi
  done

  read -r -p "Proceed? [y/N] " response
  reponse=${response,,}
  if [[ "$response" =~ ^(yes|y|like a motherfucker)$ ]]; then
    let "windex=0"
    for i in "${FILE_LIST[@]}"
    do
        mv "$i" "${NEW_NAMES[$windex]}"
        let "windex=windex+1"
    done
  fi
    
}