If you are on unix and don't care about the order of the output (or want it sorted): sort -u <file> is your friend.

Otherwise you can try:

1. Read the file into an array
2. Create a hash whose keys are the values in the array
3. Create an array from the keys of the hash
4. Print the array out to a file

------
We are the carpenters and bricklayers of the Information Age.

Don't go borrowing trouble. For programmers, this means Worry only about what you need to implement.

my $filename = ...;
local $/;
open IN, $filename;
$text = <IN>;
@words{split /\s+/, $text} = undef;
@words = keys %words;
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If you need to maintain the original order and delete subsequent duplicates, you could try this.

{
    my %seen;
    my ($in_file, $out_file) = qw| in.txt out.txt|;
    open my $in_fh, $in_file or die "$in_file: $!";
    open my $out_fh, '>', $out_file or die "$in_file: $!";
    while ( <$in_fh> ) {
        print $out_fh $_ unless $seen{$_}++;
    }
}
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use strict;
my %hash;
my $file = 'infile.txt';

open INFILE, "<$file" || die "Can't open '$file' $!\n" ;
$hash{$_}++ while <INFILE>;

open OUTFILE, ">$file" || die "Can't open '$file' $!\n" ;
print OUTFILE "$_" foreach (keys %hash);
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--Jim

Please excuse my ignorance.

Is vi a command line option?

(I suspect that your just joking with me now but...) Vi is by far the best (and cryptic) text editor. It is also one half of the eternal Vi vs. Emacs debate. Although Emacs is really more of a religion then a text editor. :)