Remove one line following a pattern in many files, and open vimdiff to confirm.

remove_line_in_many_files.sh

#!/bin/bash
confirm () {
    # call with a prompt string or use a default
    read -r -p "${1:-Are you sure? [y/N]} " response
    case $response in
        [yY][eE][sS]|[yY]) 
           true 
            ;;
        *)
           false ;;
    esac
}

for i in $(ls | cut -f1 -d. | awk '{ split($0,a,"_controller"); print a[1] }'); do 
  line=$(grep @$i -n -R . | grep where | grep ^./$i'_controll');
  number=$(echo $line | cut -f2 -d: | cut -f1 -d:)
  file=$(echo $line | cut -f1 -d:)
  param=$number"d"
  #echo $number $file
  if [ ! -n "$number" ]
  then
    echo empty
  else
    echo $number
    vimdiff <(sed $param $file) $file
    if( confirm )
    then
      sed $param $file > tmpfile; mv tmpfile $file
    fi
  fi
done