sub remove_repeated {
  my ($file_name) = @_;
  my %seen;
  local @ARGV = $file_name;
  local $^I = ".bak";
  while(<>){
    s/^\s+//;
    s/\s*$/\n/;
    next if $seen{$_}++;
    print;
  }
}

[download]

Since you consider the leading and ending white space insignificant, I didn't see a problem with removing it. If you don't want to remove the white space from the file, copy $_, trim the copy, and use the copy as the key to the hash.

Update: I had local @ARGV = @_; originally, but I reverted it back to one file name since %seen was being incorrectly shared between all the arguments.

In reply to Re: remove repeated lines with space differences by ikegami
in thread remove repeated lines with space differences by joeperl

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