Join two files on Linux

Question

I have two files; I want to join them.

$cat t1
 1 1.2
 2 2.2
$cat t2
 1
 2
 1

I want to have the output below

$cat joind.tx         


        

Answer 1

you can try AWK:

awk 'NR==FNR{a[$1]=$2}NR>FNR{print $1,a[$1]}' t1 t2