Saving output from awk into a perl variable

userix · #1 (**permalink**) 10-07-2008

How would I pass awk output to a perl variable?

For example, I want to save the value in the 4th column into the variable called test. My best guess is something as follow, but I am sure this isn't correct.

Code:

$test = system("awk '/NUMBER/{print \$4}' $_");

otheus · #2 (**permalink**) 10-08-2008

Perl supports the "backtick" operator, just as in the shell. the only difference is that Perl doesn't convert linefeeds to spaces nor squeeze extra spaces. So:

Code:

$test=`awk .... $_`;

is probably what you want.

matrixmadhan · #3 (**permalink**) 10-08-2008

Quote:

Originally Posted by userix

How would I pass awk output to a perl variable?

For example, I want to save the value in the 4th column into the variable called test. My best guess is something as follow, but I am sure this isn't correct.

Code:

$test = system("awk '/NUMBER/{print \$4}' $_");

Why don't you use the feature provided in perl itself ?

To store the 4th column value in perl,

Code:

my @arr = split(/\|/, $var);
print $var[3];

Is that what you meant ?

userix · #4 (**permalink**) 10-09-2008

I want to search for a number found in the 4th column on a specific line in a file and store that value into a variable. This file contains over 7000 lines of data. The specific line I am looking for contains the letters 'OXT' This is why I was thinking of using awk to find the line that contains 'OXT' and then grab the number from the 4th column of that line only. Would that work with split?

otheus · #5 (**permalink**) 10-09-2008

He's processing a file stored in $_. For that, the awk one-liner looks nicer. But it would normally be replaced with:

Code:

my @test;
if (open(FOO,$_)) { 
 while ($_=<FOO>) { 
   push @test,(split)[4];
 }
}
$test=join(" ",@test);

otheus · #6 (**permalink**) 10-09-2008

Absolutely. Are you looking for exactly one line, or more? Are the columns separated by whitespace? Assuming yes to all the answers above:

Code:

my $target;
if (open(FOO,$_)) { 
 while ($_=<FOO>) { 
   next unless /OXT/;  # find OXT anywhere in line.
   $target=(split)[4];
   last;
 }
 close(FOO); # forgot this last time, though not really necessary.
}
# 4th field in $target

era · #7 (**permalink**) 10-09-2008

That will only pick out the first occurrence, though. The original awk script would return all matching lines. Not hard to work around if you know any Perl, just mentioning in case you're new to this.

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