Using @ARGV with an ‘>’ in the command line

chinamox has asked for the wisdom of the Perl Monks concerning the following question:

Hello good monks!

I am working on an assignment for my an online course and I have run into a small issue. I am trying to complete an assignment involving the use of the utterly brilliant Acme::EyeDrops module.

Basically all I really need is a quick clarification on how the <> operator works. My command line input should look like this:

username$:perl my_convert_program.pl orginalprogram > program_after_Ey
+eDrops
[download]

My question to do with using @ARGV to pass the values for 'orginalprogram' and 'program_after_EyeDrops'. Are they $ARGV[0] and $ARGV2 or does the > do something like automatically open program_after_EyeDrops?

As always, thank you for your time and patience,

-mox

Comment on Using @ARGV with an ‘>’ in the command line Download Code

Replies are listed 'Best First'.
Re: Using @ARGV with an ‘>’ in the command line by GrandFather (Saint) on Nov 06, 2006 at 03:17 UTC
The '>' in the commandline redirects STDOUT at the OS level (well, shell really) to a file. Your Perl script doesn't know anything about that. Your script will get @ARGV populated with just 'originalprogram'. Anything that you `print` or would otherwise be sent to STDOUT will end up in a file called 'program_after_EyeDrops'. DWIM is Perl's answer to Gödel	[reply] [d/l]
Re^2: Using @ARGV with an ‘>’ in the command line by chinamox (Scribe) on Nov 06, 2006 at 03:33 UTC
Thank you very much for another quick and helpful response! -mox	[reply]
Re: Using @ARGV with an ‘>’ in the command line by imp (Priest) on Nov 06, 2006 at 03:21 UTC
The '>' symbol instructs the shell to redirect the STDOUT output to the file named 'program_after_EyeDrops'. The shell determines this before launching perl, and this information is not available to perl. Here's a tutorial on redirection when using bash.	[reply]
Re^2: Using @ARGV with an ‘>’ in the command line by chinamox (Scribe) on Nov 06, 2006 at 03:31 UTC
Excellent. This makes my task much easier! Thank you very much for the link too. best, -mox	[reply]
Re: Using @ARGV with an ‘>’ in the command line by smokemachine (Hermit) on Nov 07, 2006 at 23:09 UTC
if you want you can use the `>` if use `'` or `"` like: `username$:perl my_convert_program.pl orginalprogram ">" program_after_ +EyeDrops` [download] because this will make bash dont interpreter the signal...	[reply] [d/l] [select]