"tee -" duplicates stdin to stdout (maybe in interleaved order) since v5.2.1-1247-g8dafbe5; this behavior is documented as such.
But POSIX explicitly mandates different behavior: http://pubs.opengroup.org/onlinepubs/9699919799/utilities/tee.html If a file operand is '-', it shall refer to a file named -; implementations shall not treat it as meaning standard output. I assume it's too late to revert the behavior to adhere to POSIX rules as it may break existing use cases. Shall we either document that the GNU tee implementation violates POSIX, or should we go for a change to POSIX to allow this (or is there already such a discussion)? Thanks & have a nice day, Berny
