#!/usr/bin/perl
use strict;
use warnings;

my $scanword;
my $wk1;
my $wk2;
my $wk3;
my $wk4;
my $wk5;
my $wk6;
my @elements;
my $i;
my $n1;
my $inrec1='0;1;2;3;4;5;6?link=misc/redirect/ekey=BOZOTHECLOWN&dmsdate=20150210;7;8;9';
my $inrec2='0;1;2?link=misc/redirect/ekey=BOZOTHECLOWN&dmsdate=20150210;3;4;5;6;7;8;9';
my $outrec;

#####
sub special()
{

   $wk1=''; $wk2=''; $wk3=''; $wk4=''; $wk5=''; $wk6='';        #reset vars
   $wk1=$elements[$i];                                          #field number to scan
   $a=index($wk1,"?");                                          #look for ?
   if ( $a != -1 ) {                                            #? was found
      #Look for $scanword
      $wk2=index($wk1,"$scanword");                             #find start of scanword.  I.E. "ekey="
      $wk5=index($wk1,"=",$wk2);                                #find start of "="
      $wk3=index($wk1,"&",$wk2);                                #find start of next &
      if ( $wk2 != -1 ) {                                       #found scanword?
         if ( $wk3 == -1) { $wk3 = length ($wk1); }             #default to length of string if ampersand not found
         $wk4 = substr($wk1,$wk2,$wk3-$wk2);                    #wk1 is the field, wk2 is start of scanword, wk3 is the end position
         $wk6 = substr($wk1,$wk5+1,$wk3-$wk5-1);                #wk1 is the field, wk5+1 is byte after = in the scanword, wk3 is the end position

         print STDOUT "array element = $elements[$i] \n";
         print STDOUT "Found ?         in the field at offset $a \n";
         print STDOUT "Found $scanword in the field at offset $wk2 \n";
         print STDOUT "Found end       in the field at offset $wk3 \n";
         print STDOUT "Field wk4 = $wk4 \n";
         print STDOUT "Field wk6 = $wk6 \n";

         $b=$wk3-$wk5-1;                                        #length to blank
         substr($elements[$i],$wk5+1,$wk3-$wk5-1) = ' ' x $b;   #move blanks to array element
      }
   }
}
#####
print STDOUT "inrec1=$inrec1 \n";                               #print inrec
@elements = split(';', $inrec1, -1);                            #split by semicolon, -1 means to keep trailing fields if empty
$i=2;                                                           #element offset
$scanword="ekey=";                                              #text to scan for
special();                                                      #call routine
$n1=$wk6;                                                       #what was stripped out
push (@elements, $n1);                                          #add to end of array
$outrec = join(";",@elements);                                  #convert to output record
print STDOUT "outrec=$outrec  \n";                              #print output record

print STDOUT "inrec2=$inrec2 \n";                               #print inrec
@elements = split(';', $inrec2, -1);                            #split by semicolon, -1 means to keep trailing fields if empty
$i=2;                                                           #element offset
$scanword="ekey=";                                              #text to scan for
special();                                                      #call routine
$n1=$wk6;                                                       #what was stripped out
push (@elements, $n1);                                          #add to end of array
$outrec = join(";",@elements);                                  #convert to output record
print STDOUT "outrec=$outrec  \n";                              #print output record
exit;

OUTPUT EXAMPLES:

ekey is not in elements[2] so do nothing
inrec1=0;1;2;3;4;5;6?link=misc/redirect/ekey=BOZOTHECLOWN&dmsdate=20150210;7;8;9
outrec=0;1;2;3;4;5;6?link=misc/redirect/ekey=BOZOTHECLOWN&dmsdate=20150210;7;8;9;

ekey is in elements[2] so blank it in input record and add move following text BOZOTHECLOWN to a new element in array

inrec2=0;1;2?link=misc/redirect/ekey=BOZOTHECLOWN&dmsdate=20150210;3;4;5;6;7;8;9
        array element = 2?link=misc/redirect/ekey=BOZOTHECLOWN&dmsdate=20150210
        Found ?         in the field at offset 1
        Found ekey= in the field at offset 21
        Found end       in the field at offset 38
        Field wk4 = ekey=BOZOTHECLOWN
        Field wk6 = BOZOTHECLOWN
outrec=0;1;2?link=misc/redirect/ekey=            &dmsdate=20150210;3;4;5;6;7;8;9;BOZOTHECLOWN