Find and replace string in file
find dir/subdir -type f -exec sed -i 's/foo/bar/g' {} +
Find and replace file owner
find / -user oldname -exec chown newname:newgroup {} \;
Find and remove old dirs (jenkins workspaces)
find /opt/jenkins/workspace -mindepth 1 -maxdepth 1 -type d -mtime +30 -print | xargs /bin/rm -Rf