Question

input1:

1    s1
100  s100
90   s90

input2:

a    1
b    3
c    7
d    100
e    101
f    90

Output:

a    1
d    100
f    90

I know join can do this, but it needs to (1) sort these common fields (2) after join, I need to remove the second column from input1. Does anyone have better solution for this.

Answer 1

Here’s one way using awk:

awk 'FNR==NR { a[$1]; next } $2 in a' file1 file2

Results:

a    1
d    100
f    90