It's neither a bug nor undocumented.
"info ls" would have told you the following:
The permissions listed are similar to symbolic mode
specifications
(*note Symbolic Modes::.). But `ls' combines multiple bits into
the third character of each set of permissions as follows:
`s'
If the setuid or setgid bit and the corresponding executable
bit are both set.
`S'
If the setuid or setgid bit is set but the corresponding
executable bit is not set.
`t'
If the sticky bit and the other-executable bit are both set.
`T'
If the sticky bit is set but the other-executable bit is not
set.
`x'
If the executable bit is set and none of the above apply.
`-'
Otherwise.
-hpa
-- <hpa@transmeta.com> at work, <hpa@zytor.com> in private! "Unix gives you enough rope to shoot yourself in the foot." http://www.zytor.com/~hpa/puzzle.txt - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/