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Full Discussion: Perl - Grep function regular expression
Top Forums Shell Programming and Scripting Perl - Grep function regular expression Post 302446728 by adelsin on Thursday 19th of August 2010 12:08:51 PM
Old 08-19-2010
Quote:
When the file has a line with just single open paranthesis, then you will get regex error ?! What is the big deal in this ?
It would exit the program at this point.

I ended up having to go with passing $_ to a scalar variable and then placing the scalar variable into an array.

Code:
foreach (@logs){
open READ, "<$_" or die $!;
@temp=<READ>;
close READ;
    foreach (@filter){
        my $alt=$_;
        print grep {/\Q$alt\E/i} @temp ;    
        }
}

Thank you all for your help.


Quote:
If you dont understand the basics, you will end up in confusions.
This is why I'm here. I was able to figure out the problem after I thought about what was happening for awhile and researched how the grep() function operated. And remembered about Quotemetas.


Just out of curiosity, when I do the following:
Code:
foreach (@logs){
open READ, "<$_" or die $!;
#@temp=<READ>;
        foreach (@filter){
        my $alt=$_;
        print grep {/\Q$alt\E/i} <READ>;    
        }
close READ; 
}

It seems not to go through the @filter array, but rather only the first value of it. Why would this be when trying to read directly from the file?
 

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LEARN ABOUT NETBSD

lessecho

LESSECHO(1)						      General Commands Manual						       LESSECHO(1)

NAME

       lessecho - expand metacharacters

SYNOPSIS

       lessecho [-ox] [-cx] [-pn] [-dn] [-mx] [-nn] [-ex] [-a] file ...

DESCRIPTION

       lessecho is a program that simply echos its arguments on standard output.  But any argument containing spaces is enclosed in quotes.

OPTIONS

       A summary of options is included below.

       -ox    Specifies "x" to be the open quote character.

       -cx    Specifies "x" to be the close quote character.

       -pn    Specifies "n" to be the open quote character, as an integer.

       -dn    Specifies "n" to be the close quote character, as an integer.

       -mx    Specifies "x" to be a metachar.

       -nn    Specifies "n" to be a metachar, as an integer.

       -ex    Specifies "x" to be the escape char for metachars.

       -fn    Specifies "n" to be the escape char for metachars, as an integer.

       -a     Specifies that all arguments are to be quoted.  The default is that only arguments containing spaces are quoted.

SEE ALSO

       less(1)

AUTHOR

       This manual page was written by Thomas Schoepf <schoepf@debian.org>, for the Debian GNU/Linux system (but may be used by others).

       Send bug reports or comments to bug-less@gnu.org.

							     Version 444: 09 Jun 2011						       LESSECHO(1)
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