You can't cd or ls in a folder if you have no +x permissions on it. That is all. I wasted 3 hours of my life.

https://szmer.info/post/1388883

You can't cd or ls in a folder if you have no +x permissions on it. That is all. I wasted 3 hours of my life. - szmer

No one mentioned ACLs so far. If you see a + using ls -l like this drwxrwx—+, you have an access control list entry.

access control lists

An introduction to Linux Access Control Lists (ACLs)

Linux Access Control Lists, or ACLs, can take some getting used to, but they're invaluable for getting a finer-grained control of your Linux filesystem permissions.

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More than a decade of using linux and I still can’t remember setfacl syntax. I have better luck remembering tar syntax.
tar -xzf extract ze file
And tar -czf compress ze file. I saw someone post these mnemonic devices a while back and now I actually remember tar commands. Amazing!

This is a very useful way to remember it, but nowadays it’s better to drop the z (which immediately makes the mnemonic more forgettable, of course). tar can autodetect compression now, so tar -xf should work on anything from plain tar archives over tar.gz to more unusual compression algorithms like tar.xz or tar.bz2.

(the z is specifically for gzip)

You don’t even need the dash (-).