Generate network graph from command line

I recently wrote on gnuplot, today I tried another command line utility to generate graphs, graphviz, version 2.24.0 on AIX5L. Pretty straightforward syntax : (   echo "digraph Emp {"     sqlplus -s -L scott/tiger << EOF       set pages 0 lin 120 hea off feed off       select         ename ||'->'||         (select ename from emp where empno=e.mgr) || ';' […]