Honey, I broke awk! (duplicate line removal in 30M line 3.7GB csv file)

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Top Forums Shell Programming and Scripting Honey, I broke awk! (duplicate line removal in 30M line 3.7GB csv file)
# 15  
Old 03-27-2014
Originally Posted by Chubler_XL
Did you try my perl code? I have fairly high hopes it could do the job.
I'd love to but I don't know any perl. How do I handle the file I/O in perl?

# 16  
Old 03-27-2014
Save this as uniq.pl:
#!/usr/bin/perl -w
use Digest::MD5 qw(md5);
my %seen;
while (<>) {
  print $_ unless ($seen{md5($_)}++);

Then run is like this:

$ ./uniq.pl < big_ass_file_with_dups.csv > slightly_smaller_no_dups.csv

These 3 Users Gave Thanks to Chubler_XL For This Post:
# 17  
Old 03-27-2014
Goodness! I need to learn some perl!

Executed in 92 seconds! Output looks correct.


Edit: Under 64-bit Cygwin is took about 74 seconds.

Last edited by Michael Stora; 03-27-2014 at 08:09 PM..
# 18  
Old 03-27-2014
Should an md5 collision occur, it will suppress a record which should be printed. Be aware that it's possible (if not probable) that your results may incorrectly omit data.

This User Gave Thanks to alister For This Post:
# 19  
Old 03-27-2014
1 in 3x10⁸ I like those odds!
# 20  
Old 03-27-2014
Originally Posted by Chubler_XL
1 in 3x10⁸ I like those odds!
However remote the possibility, it merits mentioning in case it's a critical task.

# 21  
Old 03-28-2014
What about this ?
sort -S 1500M -T $HOME/path -u input.txt > sortedUniq.txt

-T, --temporary-directory=DIR
              use DIR for temporaries, not $TMPDIR or /tmp; multiple options specify multiple directories
S, --buffer-size=SIZE
              use SIZE for main memory buffer

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