Shell Programming and Scripting

v1 2 3 dc 5v
v2 4 5 dc 6v
v3 6 7 dc 2v

2
3
4

v1 2 3 dc 2v<-----2 is coming from file2.txt
v2 4 5 dc 3v<-----3 is coming from file2.txt
v3 6 7 dc 4v<-----4 is coming from file2.txt

awk '{getline s < "file2.txt"; $NF=s "v"}1' file1

awk '{getline s < "file2.txt"; sub(int($NF),"",$NF);$NF=s $NF}1' file1.txt

awk '{getline s < "file2.txt"; $NF=s "v"}1' file1.txt

my @arr=qw/2 3 4/;
while(<DATA>){
	s/([0-9]+)(?=[a-z]+$)/$arr[$.-1]/e;
	print;
}
__DATA__
v1 2 3 dc 5v
v2 4 5 dc 6v
v3 6 7 dc 2v

condition {action}

awk 'NR==FNR{a[NR]=$1;next}{$NF=a[FNR]"v"}1' file2.txt file1.txt