Hiya fellas- So I have this project I need to do, where the teacher sends the input a weird way and I wondered if anybody knows anything about it: The input is supposed to be read using STDIN (I'm writing it in perl but I could do it in java as well), but he is doing it some way in linux where you can specify a file on the command line when you call the program and linux sends the file via STDIN (ie instead of typing it.) Anybody know how this is done? I have access to a linux box I can test it on but I don't know the syntax...I heard something about an arrow operator? Does linux also send the end of file character? I'm trying to figure out how I can tell when I'm done with the input. My program works fine when I give it the input other ways, I just want to ensure I don't lose 60% of the points due to some stupid I/O error specific to how he's sending in the input. In case you're curious, the program converts a DFA into a regular expression. Thanks, SN

Okay, I figured out the syntax of how to test: perl 355.pl<"input.txt" Is this the only way? I think this is what he's talking about. Here's the first part of my program - Just puts all the input into $buffer. #!/usr/bin/perl $char="a"; while($char ne "") { read(STDIN, $char, 1); $buffer=$buffer.$char; } print "argument was:\n"; print $buffer; print "\nargument ended.\n" Is this obscenely inefficient? Any better ways to do it? Thanks again, -SN

There are several ways to do it. perl 355.pl input.txt #!/usr/bin/perl while(<>) { # could be written as while(<STDIN>) $line = $_; print $line; # do something with the line } ********** option 2 @file = <>; foreach (@file) { # do something } ********** option 3 { local $/; $file = <>; # entire file is loaded into $file } I can probably come up with a couple of other metods.

Fish- Thanks a lot! I like option 3...It works great in the program, and seems more elegant than using a loop. Although I don't understand how it works...what is the $/? Thanks again, -SN

$/ is the scalar that defines the input record separator (which normally is \n), but that line "undefines" it so you can slurp up the entire file into a single scalar. This is a quick and "dirty" way to read-in the file, but it could make it more difficult to work with the data, depending on what you need to do with it.

SN, I think you and I are just about the only ones on this site using Perl. For more indepth help, you might look at: experts-exchange