Daniel@0: digraph shells {
Daniel@0: 	size="7,8";
Daniel@0: 	node [fontsize=24, shape = plaintext];
Daniel@0: 
Daniel@0: 	1972 -> 1976;
Daniel@0: 	1976 -> 1978;
Daniel@0: 	1978 -> 1980;
Daniel@0: 	1980 -> 1982;
Daniel@0: 	1982 -> 1984;
Daniel@0: 	1984 -> 1986;
Daniel@0: 	1986 -> 1988;
Daniel@0: 	1988 -> 1990;
Daniel@0: 	1990 -> future;
Daniel@0: 
Daniel@0: 	node [fontsize=20, shape = box];
Daniel@0: 	{ rank=same;  1976 Mashey Bourne; }
Daniel@0: 	{ rank=same;  1978 Formshell csh; }
Daniel@0: 	{ rank=same;  1980 esh vsh; }
Daniel@0: 	{ rank=same;  1982 ksh "System-V"; }
Daniel@0: 	{ rank=same;  1984 v9sh tcsh; }
Daniel@0: 	{ rank=same;  1986 "ksh-i"; }
Daniel@0: 	{ rank=same;  1988 KornShell Perl rc; }
Daniel@0: 	{ rank=same;  1990 tcl Bash; }
Daniel@0: 	{ rank=same;  "future" POSIX "ksh-POSIX"; }
Daniel@0: 
Daniel@0: 	Thompson -> Mashey;
Daniel@0: 	Thompson -> Bourne;
Daniel@0: 	Thompson -> csh;
Daniel@0: 	csh -> tcsh;
Daniel@0: 	Bourne -> ksh;
Daniel@0: 	Bourne -> esh;
Daniel@0: 	Bourne -> vsh;
Daniel@0: 	Bourne -> "System-V";
Daniel@0: 	Bourne -> v9sh;
Daniel@0: 	v9sh -> rc;
Daniel@0: 	Bourne -> Bash;
Daniel@0: 	"ksh-i" -> Bash;
Daniel@0: 	KornShell -> Bash;
Daniel@0: 	esh -> ksh;
Daniel@0: 	vsh -> ksh;
Daniel@0: 	Formshell -> ksh;
Daniel@0: 	csh -> ksh;
Daniel@0: 	KornShell -> POSIX;
Daniel@0: 	"System-V" -> POSIX;
Daniel@0: 	ksh -> "ksh-i";
Daniel@0: 	"ksh-i" -> KornShell;
Daniel@0: 	KornShell -> "ksh-POSIX";
Daniel@0: 	Bourne -> Formshell;
Daniel@0: 
Daniel@0: 	edge [style=invis];
Daniel@0: 	1984 -> v9sh -> tcsh ;
Daniel@0: 	1988 -> rc -> KornShell;
Daniel@0: 	Formshell -> csh;
Daniel@0: 	KornShell -> Perl;
Daniel@0: }