create an ascii progress bar
J, 78×0.75 = 58.5

'w p'=:_".1!:1]3
1!:2&amp;4('%',~":100*p)(i.@[-&lt;.@-:@-)&amp;#}'[]'0 _1}' |'{~(w*p)&gt;i.w



$ echo -n 79 0.15 | jconsole test.ijs
[|||||||||||                          15%                                     ]
$ echo -n 25 0.76 | jconsole test.ijs
[||||||||||76%|||||     ]   
$ echo -n 39 -0.12
[                 _12%                ]
$ echo -n 25 7.6 | jconsole test.ijs
[|||||||||760%||||||||||]   


(Negative numbers in J are prefixed by _, not -.  Luckily, dyadic ". can parse both formats.)