find lines in file1.txt not found in file2.txt memory problem


 
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# 1  
find lines in file1.txt not found in file2.txt memory problem

I have a diff command that does what I want but when comparing large text/log files, it uses up all the memory I have (sometimes over 8gig of memory)

Code:
diff file1.txt file2.txt | grep '^<'| awk '{$1="";print $0}' | sed 's/^ *//'

Is there a better more efficient way to find the lines in one file that aren't found in another file?
Thanks
# 2  
What does your input look like and what should your output look like?
# 3  
It should get the lines in file1.txt not found in file2.txt For example:

Code:
File1:

000
555
aaa
ccc
jjj
zzz

Code:
File 2:

000
ccc
111
hhh
vvv

when I run the command it should get:

Code:
555
aaa
jjj
zzz

---------- Post updated at 08:10 PM ---------- Previous update was at 04:25 PM ----------

The error that I would get when using this diff command on large files is:

diff: memory exhausted

any ideas for alternative commands that do the same thing but doesn't use as much memory?
# 4  
AFAIK your two options are use a lot of memory, or use a lot of time. is file1 8G?
# 5  
It is only 2gigs but for some reason it uses more than 8gigs of memory
# 6  
You might get lucky with the following grep approach. It should consume less memory than your diff solution:
Code:
grep -vxFf file2 file1

If file2 is large and contains many duplicates, filtering it through sort|uniq would help.


Regards,
Alister
 

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