Please read How (Not) To Ask A Question. In particular, could you please post some sample data, along with exactly what parts you're trying to extract, and what the criteria are? Reread your question from the point of view of someone who doesn't already know what you want, and I think you'll see that you're leaving out pretty much everything we need to know.

Update: Now there's some data, but still no real specification of how your parameters are separated or what's really going on here. It looks like this may do what you want, but if not you'll have to step back for a moment and think about what you're doing.

#!/usr/bin/perl -l

use strict;
use warnings;
use Data::Dumper;

my %variables;

undef $/;
$_ = <DATA>;
while (s/\s*(\w+)\s*=\s*([^=]+)\s*\z//){
  $variables{$1} = $2;
}

print Dumper(\%variables);
__DATA__
drsubc  = agauss(0, 1, 3)   delm1   = '0 + 0.045u*distm1'             
+  delm2 = '0 + 0.07u*distm2'        delm3   = '0 + 0.07u*distm3'     
+           delm4 = '0 + 0.07u*distm4'                delmt   = '0 + 0
+.07u*distmt' delml   = '0.16u + 0.43u*distml'            delam   = '0
+.32u + 0.86u*distam'         dele1   = '0 + 0.25u*diste1'            
+    dele2   = '0 + 0.25u*diste2'                delma   = '0.16u + 0.
+6u*distma'             pmsxt   = 'npmsxt + 12.5u*dpmsxt'           ti
+h     = 0.35u                capct   = '0.50u + 0.13u*xdcapct'       
+    capcti  = '0.55u + 0.13u*xdcapct'           m1t     = '0.41u + 0.
+05u*xdm1t'    m1ti    = '0.36u + 0.05u*xdm1t'             m2t     = '
+0.48u + 0.057u*dm2t'             m3t     = '0.48u + 0.057u*dm3t'     
+        m4t     = '0.48u + 0.057u*dm4t'             mtt     = '0.48u 
++ 0.057u*dmtt'             qtt     = '0.242u + 0.0202u*dqtt'         
+  htt     = '0.242u + 0.0202u*dhtt'       mlt     = '2.0u + 0.2u*dmlt
+'                amt     = '4.0u + 0.4u*damt'               e1t     =
+ '3.0u + 0.5u*de1t'            e2t     = '4.0u + 0.5u*xde1mat'       
+      mat     = '4.0u + 0.4u*dmat'                m1m2t   = '0.35u + 
+0.05u*dm1m2t'
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