What do you mean exactly by "arbitrary"? If it means a constant, known at run-time, number of spaces, then it's easy, just do a split on that number of spaces. If you mean random, unknown and different from line to line, then the answer is easy: with the information you give, you can't. In your example, there is no way to know where to split Genesis Chamber Mark Tedin in 2 strings.

Now all is not lost, you can try various heuristics to figure out what to do, but remember # 11953 Of course, this is a heuristic, which is a fancy way of saying that it doesn't work (from MJD):

#!/usr/bin/perl -w
use strict; 

while( <DATA>)
  { if( m{^\d+     # initial digits (1rst field)
           \s+     # separating space(s)
           (.*?)   # the 2cd and 3rd field
           \s+     # separating space(s)
           \S      # 1 (non-space) character (4th field)
           \s+     # separating space(s)
           \S      # 1 (non-space) character (5th field)
           \s*     # you might or might not want to allow extra spaces
+ a the end of the line
          $}x
      )
      { my $fields= $1;
        my @fields;

        # @fields= heuristic1( $fields) || heuristic2( $fields);
        # does not work as the || seems to put the first function call
+ in scalar mode, weird

        @fields=  heuristic1( $fields);
        unless( @fields) { @fields=  heuristic2( $fields); }

        if( @fields)
          { print "field 2: '$fields[0]' - field 3: '$fields[1]'\n"; }
        else
          { warn "cannot extract field 2/3 of line $. Fields are: '$fi
+elds'\n"; }
      }
    else
      { warn "can't parse line $."; }
  }

# only 2 words, that's easy
sub heuristic1
  { my $fields= shift;
    my @fields= split /\s+/, $fields;
    if( @fields == 2) { return @fields }
    else              { return; } 
  }

# more than one space separates the 2 fields
sub heuristic2
  { my $fields= shift;
    my @fields= split /\s\s+/, $fields;
    if( @fields == 2) { return @fields }
    else              { return; } 
  }


__DATA__
122     Genesis Chamber             Mark Tedin                A     U
123 f2w f3w 4 5 
123 f2w1 f2w2  f3w 4 5 
123 f2w1 f2w2  f3w1 f3w2 4 5 
123 f2w f3w 4 99 
123 f2w1 f2w2 f3w1 f3w2 4 5
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