From mboxrd@z Thu Jan 1 00:00:00 1970 From: ron@ronnatalie.com (Ronald Natalie) Date: Sat, 10 Sep 2016 22:41:52 -0400 Subject: [TUHS] Shell control through external commands In-Reply-To: <201609110239.u8B2dgDJ010272@freefriends.org> References: <201607151647.u6FGlqvW037575@tahoe.cs.Dartmouth.EDU> <20160910174011.GF5970@dnied%tiscali.it> <006301d20bcb$43ae03b0$cb0a0b10$@ronnatalie.com> <201609110239.u8B2dgDJ010272@freefriends.org> Message-ID: > On Sep 10, 2016, at 10:39 PM, arnold at skeeve.com wrote: > > "Ron Natalie" wrote: > >> Traditionally, the shell recognized shell scripts and ran them in a new >> instance of the shell rather than calling exec on them. > > I think that the way the shell "recognized" scripts was by having > exec fail, otherwise how would it know? I think we'll have to go > grubbing in the source archives to be sure. You are correct. > >> It was a Berkeley hack to add a new exec magic number that happened to >> correspond to the characters #!. > > ISTR reading on this list that #! was a post-V7 Bell Labs invention > that the BSD guys went and implemented themselves... That’s possible. We jumped from V7 to the BSD distributions because about the same time we were going from PDP-11’s to VAXen of various flavors (actually our first VAX was a copy of one of the George Gobel dual processor 780’s).