Mac freezes at startup at apple logo after permission changes I executed

chmod go-rwx /


Command on my Macbook pro yosemite. Since then its not able to boot up. It just sticks at apple logo.

Things I have tried:


Mac repair  > Disk Utility > Repair file permissions. Completed Ok.
Mac repair > Disk Utility >  Repair Disk. Completed Ok.
Pressed (Cmnd+S) during boot > fsck -fy . The volume appears to be Ok.
Pressed (Cmnd+S) during boot > verified permissions of all folders inside the / with another mac book of same specs. All were same.


Am I only left with re-install ?

Ps: I got that command from here: https://stackoverflow.com/a/6419695
Assuming you didn't change ownership (users/groups) but instead only changed the permissions...

Try issuing the command:

chmod 1775 /