A solution (although it migh be a BadIdea and misguided would be)

### in hello.pl
print "Hello";

### in goodbye.pl
print "goodbye";

### in choose.pl
require shift() . ".pl";
[download]

Then fromt he command line perl choose.pl hello would run the hello code, and the same for goodbye. You should definitly verify that the input is a real file that you want to allow them to run etc., but this should get you started down this path. In general i would think it is a bad idea and would rethink what you are doing to see if it fits in some differen t model better.