martyn@localhost ~ $ /var/log/Xorg.0.log
bash: /var/log/Xorg.0.log: Permission denied
martyn@localhost ~ $ sudo /var/log/Xorg.0.log
sudo: /var/log/Xorg.0.log: command not found
martyn@localhost ~ $ su /var/log/Xorg.0.log
Unknown id: /var/log/Xorg.0.log
martyn@localhost ~ $ su haggis1a /var/log/Xorg.0.log[A
Unknown id: haggis1a
martyn@localhost ~ $ su haggis1a /var/log/Xorg.0.log
Unknown id: haggis1a