On 07/28/2010 05:53 PM, Stuart Cooper wrote:
> Hi Damian,
>
>> my $first_line = `grep -v '#' $filename|head -n 1`; # to get the first
>> non-comment line
>
--extra code deleted--
> It's a broken pipe because the right side of it is not valid.
Could you elaborate on why? I tried it and it worked for me.
>
> Try playing around with this 10-liner:
>
> #!/usr/bin/perl
> use strict;
> use warnings;
>
> $SIG{'PIPE'} = 'IGNORE';
> # $SIG{'PIPE'} = 'DEFAULT';
>
> my $filename = '/etc/apache2/apache2.conf';
> my $first_line;
>
> # $first_line = `grep -nv '#' $filename| misspelledhead -n 1`; # to
> get the first non-comment line
> $first_line = `grep -nv '#' $filename| head -n 1`; # to get the first
> non-comment line
>
> print "first non comment line is $first_line";
>
> Good luck,
> Stuart.
In fact, I tried your code snippets as well as the OP's, and the only
error I saw, with a misspelled command name, was:
sh: ehead: command not found
I tried this without changing any signal and with "$SIG{'PIPE'} =
'IGNORE'", no difference.
In other words, the shell, when setting up the command, verifies it can
find all commands in the pipe sequence before it tries anything else.
Now, when I gave 'head' an invalid option, so it was found and ran, but
exited *without* reading the input, then I got the broken pipe error.
But I also got an error from 'head' about invalid options.
Bottom line is I can't figure out what it is that is 'not valid' in the
original?
--
Bob McGowan
