Parse $val to return true or false
Transform a duration in second to a string in form of day/hours/minutes/seconds.
Return in minutes a human readable value like 2d or 3h
Change effective user and group to $user and optionnal $group.
Return arrayref containning old uid and gid on success. Return undef and error message on failure.
Olivier Thauvin <firstname.lastname@example.org>