replace.sh

#!/usr/bin/env zsh
#
# REPLACES STRINGS IN TEXT-BASED FILES
#
# replace <old string> <new string>
#

setopt extendedglob

# Dependency check
function die {
  print >&2 "$@"
  exit 1
}

for command in file; do
  (( ${+commands[$command]} )) || failed+=($command)
done

if (( $#failed )); then
  die "Not found: $failed"
fi

echo "Replacing $1 with $2..."

for file in **/*; do

  # Match text files
  if file -b $file | grep -q "text" && grep -q -- "$1" $file; then

    # Sed in-place editing doesn't work the same way on BSD, so use temporary file instead
    sed "s/$1/$2/g" $file > $file.tmp
    mv -f $file.tmp $file

    echo "$file"
  fi
done