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