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In a huge file, Delete duplicate lines leaving unique lines

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# 8  
Old 08-02-2011
Excuse me but "sort -m". This will require much less memory.

OOPS. Yes. With -m it's possible that duplicates can stay. But if the last sort wouldn't work (because of lack of memory), then it's possible "sort -m | uniq"
# 9  
Old 08-02-2011
Quote:
Originally Posted by yazu
Excuse me but "sort -m". This will require much less memory.
Consider the following:

Code:
% cat infile 
adsf123
asdlfkjlasdfj
adsf123
asdfasdf12341234
asdfasdf12341234
asdlfkjlasdfj343
asdlfkjlasdfj56
adsf123
asdlfkjlasdfj
adsf123
asdfasdf12341234
asdfasdf12341234
asdlfkjlasdfj343
asdlfkjlasdfj56
% split -l 5 infile 
% for f in x*; do sort -u "$f" > "$f"_sorted; done
% sort -m x*_sorted
adsf123
adsf123
asdfasdf12341234
asdfasdf12341234
asdlfkjlasdfj
asdlfkjlasdfj
asdlfkjlasdfj343
asdlfkjlasdfj343
asdlfkjlasdfj56
asdlfkjlasdfj56

Or you were suggesting something different?
This User Gave Thanks to radoulov For This Post:
yazu
# 10  
Old 08-02-2011
Yes. You are very right. I've corrected my previous post.
# 11  
Old 08-02-2011
I am trying the split and sort, I will let you know once it is done. Meanwhile, I have a doubt, why can't we implement something like below so that it will not take much space ..
for line in `cat infile`
do
#delete all lines in infile matching $line leaving 1 $line#
done
exit 0
# 12  
Old 08-02-2011
Because this is O(n^2) algorithm. And for 4GB file it will work really very long. (Days, months? Who knows... Smilie )
# 13  
Old 08-02-2011
sort: write failed: /tmp/sortmO2esr: No space left on device
during the last sort execution.
# 14  
Old 08-02-2011
'man sort' yields:
Code:
       -T Directory
            Places all temporary files that are created into the directory specified by the
            Directory parameter.

specify '-T' with the directory with 'enough' space for the temp files.
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