#!usr/bin/perl
use warnings;
use strict;
#
my ($line)= "4.62399E+09  2.90871E+09  7.17338E+14";
my ($oldline) = "4.62399E+09  2.90871E+09  7.17338E+14";
my ($newline) = "4.62399E+09  2.90871E+09  ";
#
    open (IN, "sdef");
      while (<IN>) {
          if ($_ =~ /sb1       1.0  142r/ ) {
             $oldline = substr($line, 10, 38);
             $newline = substr($oldline, 0, 26);  
           } else {
             $line = $_;
           }
      }
    close(IN);
#
    chomp($oldline);
    chomp($newline);
    print "new = $newline\n";
    print "old = $oldline\n";
#
    open (IN, "sdef");
      open (OUT, ">sdef_steel")  or die "Cannot open file for writing: $+!" ;
       while (<IN>) {
           s/si1 L      1000   1000   /si1 L      1000   /; # works ok
           s/2150   2151   1035/2150   2151       /;       # works ok
           s/$oldline/$newline/;                        # doesn't work
           s/sp1 D     (\d+.\d+E[-+]\d+)  /sp1 D     /;    # works ok
           print OUT $_;
       }
       close (IN);
       close (OUT);