Use chmod When
The owner is correct but the permission bits are too strict or too loose.
You need to grant execute, read, or write access appropriately.
Compare
chmod vs chown
How to distinguish file permission changes from ownership changes.
`chmod` changes permission bits such as read, write, and execute. `chown` changes which user or group owns the file. They often appear together, but they solve different problems.
Use chown When
The file belongs to the wrong user or group.
The access issue comes from ownership, not from the permission bits themselves.
Rule of Thumb
chmod changes access rules. chown changes ownership.
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