Find records between two files which are not exists in one another in one

Shell Programming and Scripting
1

Hello all,

Would like to know how to find records between two files which are not exists in one another in one. For example: I've two files "fileA" and "fileB" and want to find record from "fileB" which does not exists in "fileA".

fileA
--------
ABCD
DEFG
GHIJ
KLMN
NOPQ
RSTU
VUWX
XYZA

fileB
--------
ZYXW
ABCD
VUVS
RQPO
NMLK
JIHG
FEDC
BAZY
KLMN
RSTU

From above, the expected result must be,

fileC
--------
ZYXW
VUTS
RQPO
NMLK
JIHG
FEDC
BAZY

Please advise how to handle such cases from command line.

Thanks,
Venkat

2

Finds records from fileB which are not in fileA:

awk 'NR==FNR{a[$0]; next}!($0 in a)' fileA fileB

---------- Post updated at 06:35 AM ---------- Previous update was at 06:34 AM ----------

:wall:I have post code of this like for more than once...

3

:smiley:

You could also use grep if your grep version supports the -f option:

grep -v -f fileA fileB
1 Like
4

I really like this one :b:

5

You could also use the comm tool. See the comm man page.

Regards,
Mark.

6

This really looks cool, but it can be much slower than the awk solution if fileA is large since grep has to take each line in fileA as a Regex, and greps against the whole file of fileB.:slight_smile: