3
node [fontsize=24, shape = plaintext];
15
node [fontsize=20, shape = box];
16
{ rank=same; 1976 Mashey Bourne; }
17
{ rank=same; 1978 Formshell csh; }
18
{ rank=same; 1980 esh vsh; }
19
{ rank=same; 1982 ksh "System-V"; }
20
{ rank=same; 1984 v9sh tcsh; }
21
{ rank=same; 1986 "ksh-i"; }
22
{ rank=same; 1988 KornShell Perl rc; }
23
{ rank=same; 1990 tcl Bash; }
24
{ rank=same; "future" POSIX "ksh-POSIX"; }
47
KornShell -> "ksh-POSIX";
51
1984 -> v9sh -> tcsh ;
52
1988 -> rc -> KornShell;