Question

I found (and adapted a bit) a command to edit a list of files using regex (and perl). I put it into a script file called cred, so I can do cred . england England to replace all occurrences of england with England in all files in the current directory.

find $1 -type f -exec perl -e 's/'$2'/'$3'/g' -p -i {} \;

It is wicked powerful, and already useful – but dangerous, and flawed. I would like it to…

1. preview changes (or at least files operated on) first, asking confirmation
2. work with longer strings than a single word. I tried cred . england 'the United Kingdom' but it fails

I would also be interested in other (short and memorable, universally installed/installable on osx and ubuntu) commands to achieve the same thing.

EDIT:

This is what I have so far – open to improvements…

# highlight the spots that will be modified (not specifying the file)
find $1 -type f -exec grep -E "$2" --color {} \;
# get confirmation
read -p "Are you sure? " -n 1 -r
if [[ $REPLY =~ ^[Yy]$ ]]
then
  # make changes, and highlight the spots that were changed
  find $1 -type f -exec perl -e "s/$2/$3/g" -p -i {} \;
  echo ""
  find $1 -type f -exec grep -E "$3" --color {} \;
else
  echo ""
  echo "Aborted!!"
fi

Answer 1

To work on strings with spaces, write your command like:

perl -e "s/$2/$3/g"

If you use double quotes, variables will be expanded inside the quotes.

To do something like previewing changes and asking for confirmation you will need a much more complex script. One very easy thing to do would be to just run find $1 -type f first to get a listing of all the files, and then use the read command to get some input and decide if you should continue.