Greetings, and thank you for your reply.
After adding
print "Content-type: text/html\n\n";
I attempted to use your example, however, it failed to produce any output (to the browser).
Perl complained (rightfully) about
( Insecure $ENV{PATH} while running with -T switch )
So modified it as follows:
use Modern::Perl;
my @l = system(`ls -1b`);
my $c = 0; # toggle for odd/even lines
for (@l){
chomp;
my $bg = $c ? "#eee" : "#ccc";
say qq| <p style="font-family:mono;background:$bg">$_</p> |;
$c = 0 if $c++ == 1;
}
Which produces one line with a grey background, that simply has a -1 in it.
I'm confused. Any further thoughts?
Thank you again for your response.
use perl::always;
my $perl_version( 5.12.4 );
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Why did you change my line:
my @l = `ls -1b`;
to:
my @l = system(`ls -1b`);
? Mine runs the ls command in a subshell and returns the results to the @l array, one line per array element. Yours runs ls in a subshell and captures the output, but then passes that output to system, which tries to run that in another sub-process, passing the return value of that sub-process to @l, making it the first (and only) element. Odds are very good that a listing of the files in your directory doesn't make a valid system command (and could possibly make a harmful one), so the return value is an error number, in this case, -1, 'failed to execute'.
See perlipc and other docs on the difference between system and backticks, as well as other ways to run a sub-process and capture the output, like opening a pipe:
open my $pipe, '-|', 'ls -1b' or die $!;
while(<$pipe>){
chomp;
say qq| <tag attr='value'>$_</tag> |;
}
close $pipe;
There are a lot of different ways to do this. Perl isn't called a glue language for nothing. But some are usually better than others, depending on the circumstances.
Aaron B.
Available for small or large Perl jobs; see my home node.
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Greetings, and thank you for taking the time to help me on this.
EUREKA!
I maintained the previous revisions I made to your original reply. But,
removed the system() call -- retuning it to `ls -1b`;
It appears that the only issue I had with yours originally, was the single quote marks
used in the HTML
formatting -- ' vs ".
For clarity (and anyone else that might be interested):
#!/usr/bin/perl
print "Content-type: text/html\n\n";
use strict;
use diagnostics -verbose; # Desperately seeking guidance :P
use Modern::Perl;
my @l = `ls -1b`;
my $c = 0; # toggle for odd/even lines
for (@l){
chomp;
my $bg = $c ? "#eee" : "#ccc";
say qq| <p style="font-family:mono;background:$bg">$_</p> |;
$c = 0 if $c++ == 1;
}
# use strict; with use Modern::Perl; is redundant
# keeping use strict; and commenting use Modern Perl;
# would require changing "say" to "print"
Thank you VERY much. The output is beautiful! :)
#!/usr/bin/perl -Tw
use perl::always;
my $perl_version = "5.12.4";
print $perl_version;
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