Writing to command line when prompted

[Mahoota]

I have created a perl program that asks for the name of an input filename; then an output file; and then reads in these filenames and opens the relevant files using STDIN (performs operations on the data from the infile and writes results to the outfile).

I now need a second program that will run this program (>perl progname), then enter the filenames when prompted at the command line.

I can't seem to get open() to do this, and dont know if there is a way of editing the first program to read in filenames directly from the executable line (>perl progname filename) (then I could simply use system() in the second program..

Any ideas greatfully recieved.