I accidentally ran a
chmod 754 ./ when I was at the root directory on the server which runs Ubuntu 18.04.
Now I cannot use commands like
pkexec, nor can I change anything. What should I do? Does it affect other user?
chmod, i.e. the ONLY file/directory that you modified was
If you found this question and answer through a search engine and used the recursive (
--recursive) method, please go here!
I ran the exact command you posted in your question on a VM, and recovered it with (almost) no trouble at all.
Since you only modified one directory/file, the solution is simple: just change it back!
You actually don't need a Live CD to fix this. Ubuntu has a built-in recovery mode. These steps assume your computer started turned off.
chmod 755 /Enter
That's it! Unless there were any other complications, your system is recovered.