File::Remote wierdness. (problems using strict?)

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

Consider the following code:

#!/usr/bin/perl
use strict;
use File::Remote;
my $rp=new File::Remote(
        rsh=>"/usr/bin/ssh",
        rcp=>'/usr/bin/scp');

$rp->open (ARPFILE,"xeng-mon01:/usr/local/router-walk/data/arp.csv")
        or die $!;

my $line=<ARPFILE>;
print $line;
[download]

When that is run I get an error:

Bareword "ARPFILE" not allowed while "strict subs" in use at testFileR
+emote.pl line 8.
[download]

which confuses the heck out of me. When I do something like

#!/usr/bin/perl
use strict;

open FIN,"</etc/passwd" or die $!;

my $line=<FIN>;
print $line;
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it gives me the first line of my /etc/passwd file just like I'd expect. What gives here? Anybody else see this?

Or am I getting senile in my old age?

UPDATE: Since posting this and before reading the replies from folks (Thanks shmem, rblaschand Herkum!) I had two beers and tried an experiment and it worked. By changing the first example's open call to

$rp->open(*ARPFILE....
[download]

strict was happy again. Then I read the replies and discovered why it worked. Thanks again gang! </code>

Peter L. Berghold -- Unix Professional
Peter -at- Berghold -dot- Net; AOL IM redcowdawg Yahoo IM: blue_cowdawg

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Re: File::Remote wierdness. (problems using strict?) by shmem (Chancellor) on Jun 21, 2006 at 18:11 UTC
maybe... ;-) but `$rp->open` is just a sub, not even prototyped, so it's first argument isn't made into a filehandle. Hint: what happens if you use `$rp->open (*ARPFILE,"xeng-mon01:/usr/local/router-walk/data/arp.csv")`? cheers, --shmem _($_=" "x(1<<5)."?\n".q·/)Oo. G°\ / /\_¯/(q / ---------------------------- \__(m.====·.(_("always off the crowd"))."· ");sub _{s./.($e="'Itrs `mnsgdq Gdbj O`qkdq")=~y/"-y/#-z/;$e.e && print}	[reply] [d/l] [select]
Re: File::Remote wierdness. (problems using strict?) by Herkum (Parson) on Jun 21, 2006 at 19:51 UTC
As the previous poster stated, you are not calling open directly. You are calling the method $r->open(). A method is going to expect that you are passing an array of values. Unqouted words have different means with different context, `my %hash = ( red => 'car' ); # Hash context` [download] `last STATEMENT; # label context` [download] `open FILE, "my_file.txt"; # file handle context` [download] `$r->open( ARGS ); # looking for an array, and the interpreter is thin +king, # it cannot be a label or file handle and it is not + a hash, WTF?` [download] I hope that helps some. Context of certain syntax can be confusing if you had not been doing it for a while, a loooong while! :) Note: This is within the context of 'use strict'.	[reply] [d/l] [select]
Re: File::Remote wierdness. (problems using strict?) by rblasch (Monk) on Jun 21, 2006 at 19:43 UTC
Not sure if I get everything right, but here's the story. Usually, under `use strict` you are not allowed to use barewords like `ARPFILE`. A bareword is something perl "can't make sense of," thus it treats it as a quoted string `'ARPFILE'` if there isn't any stricture. That's why you get the error. Unusually, there are some internal functions, like your `open` example, where barewords are okay, even under `use strict`, because they are meant as handles. `opendir`, `sysopen` and a few others seem to fall into this category. That's why your last example `open FIN,"</etc/passwd" or die $!;` works fine, even if `FIN` is a bareword. Your call to File::Remote::open `$rp->open (ARPFILE,...)` on the other hand is nothing but a plain method call, hence the error. It wouldn't be Perl if there weren't a few ways to solve this. Here's how I would do it. I prefer lexicals, so I'd create an anonymous glob with `gensym` using Symbol. Then one can usually use `$arpfile` like any other handle. Note that the following is untested. `#!/usr/bin/perl use strict; use warnings; use File::Remote; use Symbol; my $rp = new File::Remote( rsh=>"/usr/bin/ssh", rcp=>'/usr/bin/scp'); my $arpfile = gensym; $rp->open ($arpfile,"xeng-mon01:/usr/local/router-walk/data/arp.csv") or die $!; my $line=<$arpfile>; print $line;` [download] Let me know if this is working for you.	[reply] [d/l] [select]