In pset7 my register.php was working fine until I executed chmod 600 register.php after which register_form isn't opening anymore. It shows the following error: enter image description here Is there a way to undo a permission change??

1 Answer 1


I know of no way to "undo" or roll back a permission change, but you can always change the permissions to whatever you want, using the same command and a different 3-digit number.

By changing it to 600, you locked it out to other people and systems. The first digit, the 6, is your, the owner, permissions. The second is group permission and the third digit is permission for anyone or anything else. By setting them to 0, you denied permission to the rest of the world.

You should review what each permission level is, from 0 to 7, or by name, and assign the appropriate permissions to the file. I'll leave it to you to research these, as it is important for the future and your education on this topic to thoroughly understand them. Start by reading the man page for chmod. A google search will be productive too.

If this answers your question, please click on the check mark to accept. Let's keep up on forum maintenance. ;-)

  • thanks for your help, I finally figured it out. -@Cliff Nov 26, 2016 at 11:42

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