Recursively changing linux directory and file permission

Q How do I recursively change files with 777 permissions to 755 in /home/user/demo directory? I have a number of files in this directory and I need to change from 777 to only if that file has 777 permissions. A To change file access permissions you use chmod command. It has -R or -recursive option that change files and directories recursively. For example $ chmod -R 0755 directory