What Does S Mean in Unix Permissions?

s (setuid) means set user ID upon execution. If setuid bit turned on a file, user executing that executable file gets the permissions of the individual or group that owns the file.

What is S in chmod permissions?

This “s” indicates the file has the setuid bit set.

The passwd command will always run with root privileges no matter who launches it because the owner of the file is root. We can use the chmod command to set the setuid bit on a file: chmod u+s FILE.

What is S in file permissions in Linux?

Instead of the normal x which represents execute permissions, you will see an s (to indicate SUID) special permission for the user. … Likewise, rather than the usual x which represents execute permissions, you will see an s (to indicate SGID) special permission for group user.