Re: how to read perl variable from a line read from a file

[Anonymous Monk]

Hopefully a less hackish (safer) solution than what has been offered so far. We use a hash called %vars to contain your variables because it's simply a good idea.

use Data::Dumper;

my %vars;

# set initial variables
$vars{'INST'} = 'C';

open my $fh, "<", 'file' or die $!;
while (<$fh>) {
    chomp;
    m/^(\w+)=(.*)$/ or next;
    my ($var, $value) = ($1, $2);

    $value =~ s/\$([a-z]+)/ $vars{$1} /gie;
    $vars{$var} = $value;
}

print Dumper(\%vars);

# source file:
VAR1=$INST/dirivebase/program
VAR2=$INST/origbase/data

# output:
$VAR1 = {
          'VAR1' => 'C/dirivebase/program',
          'INST' => 'C',
          'VAR2' => 'C/origbase/data'
        };

You might want to adjust the regexp to be more lenient towards spacing, though...

[Bharath666]

Thanks!! Its working now....

[Anonymous Monk]

It's not perfect. It's missing a close $fh and the substitution regexp probably should be s/\$([a-z]+)/ $vars{$1} || "\$$1" /gie; to give a somewhat sane behaviour for undefined variables (instead of substituting them with the empty string. Which is what *nix shells do, so I guess it's not that bad...)