Comparing files

soliberus · #1 (**permalink**) 04-25-2008

I have a file called X, which contains the following:

10
100
200
300

I then have file Y, which containts the following:

10
200
500
800

I want to write a script that will compare the contents of Y with the contents of X and ONLY return values in Y that does not exist in X (output to file Z).

Could someone please point me in the right direction?

Thanks

jim mcnamara · #2 (**permalink**) 04-25-2008

Code:

awk ' FILENAME=="X" {arrx[$0]++}
       FILENAME=="Y" {arry[$0]++}         
     END {for (i in arry) 
         {if(arrx[i]==0) {print i}  } }'  X Y > newfile

Sample run with code in t.awk:

Quote:

csadev:/home/jmcnama> cat X Y
1
2
3
4
5
6
8
9
10
1
2
3
4
5
6
7
8
9
10
csadev:/home/jmcnama> t.awk
csadev:/home/jmcnama> cat newfile
7

era · #3 (**permalink**) 04-25-2008

If your fgrep supports the -f option, you can do

Code:

fgrep -vxf X Y

There are various more tedious ways to express this, e.g. using a sed script which you'd construct from the contents of X. Search the forums for "fgrep -f" "sed" or someething like that to see the numerous earlier threads on similar topics.

vgersh99 · #4 (**permalink**) 04-25-2008

look into 'man comm'

soliberus · #5 (**permalink**) 04-25-2008

thank you all for your replies

in this instance fgrep -vxf works the best. thank you era

summer_cherry · #6 (**permalink**) 04-29-2008

Does not this one address your issue?

Code:

comm -13 file1 file2

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