Permission denied

When I tried to run one of my php script, i threw this error. Error: Warning: Unknown: failed to open stream: Permission denied in Unknown on line 0 Fatal error: Unknown: Failed opening required ‘/opt/lampp/htdocs/reroute/index.php’ (include_path=’.:/opt/lampp/lib/php’) in Unknown on line 0 Happened due to read/write access permission. Because Linux system maintains permission level very strictly. […]