Grep the lines in one file that are also in another

Shell Programming and Scripting
1

Hi all,
I have two files.
File A looks like this:

abkhasian	com|hum
accent	com|com|com|com|sta
acceptation	act|com|sta
adventures 	com|hum
adversity	com|hum|hum

and File B looks like this:

adventure
adventures
adversary
Adverse
adversity

I want to print those lines in File A in which the value in Column 1 also appears in File B.

Thus, the desired output would be to print those lines from File A:

adventures 	com|hum
adversity	com|hum|hum

I know there is a grep that does the opposite of that:

grep -F -x -v -f fileB fileA

But, is there a way to modify it so that I can reach my desired output?
Thank you

2

Hello owwow14,

Here is an awk approach for same.

awk 'FNR==NR{A[$1]=$0;next} ($1 in A){print A[$1]}' fileA fileB

Output will be as follows.

adventures      com|hum
adversity       com|hum|hum

Thanks,
R. Singh

1 Like
3 
awk 'FILENAME=="FileA" {arr[$1]++; next}
       FILENAME=="FileB" {if($1 in arr) {print $1} }' FileA FileB >output

awk works well for this

4 
awk 'FNR==NR{A[$1];next}$1 in A' FileB FileA
5

Hello Akshay,

I think you need to assign the value to A[$1]=$0 . As it will give only the first column of fileB.

awk 'FNR==NR{A[$1]=$0;next} ($1 in A){print A[$1]}' fileA fileB

Thanks,
R. Singh

6

Could you please explain me Mr.RavinderSingh13 why I need to assign the value unnecessarily ? I read FileB first not FileA please look into the post.

Thanks by the way :o

1 Like
7

Hello Akshay,

I got your point. Thank you for explaining me same.

Thanks,
R. Singh

8

No surprise man if you reverse files :slight_smile:

9

Why not

grep -ffileB fileA
adventures     com|hum
adversity    com|hum|hum
10

I like things that are easy to read, imho makes it simpler to maintain later on...

while read line;do
   grep ^$line[[:space:]] fileA
done<fileB