How to replace text

sudo sed -i "s'fastcgi_pass   php5-fpm;'fastcgi_pass   php;'" /etc/nginx/sites-enabled/*

sed -i 's/UNIX/Linux/g' input.file

#!/bin/bash
for f in /path/to/*.doc
do
   sed -i  's/UNIX/Linux/g' "$f"
done

find . -type f -print0 | xargs -0 sed -i 's/Application/whatever/g'