Shell Programming and Scripting

awk '$3 == "A" {print $0}' file.txt > newfile.txt
awk '$3 == "B" {print $0}' file.txt >> newfile.txt

awk '$3=="A";$3=="B" {print $0}' file.txt

awk '$3 ~ /A/ || $3 ~ /B/' file.txt

$ awk '$3 ~ /A|B/' file

awk '$3=="A" || $3=="B"  {print $0}'  file.txt

$ cat <<test | awk '$1 ~ /A|B/'
A
C
B
BB
D
test
A
B
BB

$ cat <<test | awk '$1 ~ A || $1 ~ B' # Variable  ???
A
C
B
BB
D
test

A
C
B
BB
D

$ cat <<test | awk '$1 ~ /A/ || $1 ~ /B/'
A
C
B
BB
D
test

A
B
BB

$ cat <<test | awk '$1 ~ A || $1 ~ B' A=A B=B
A
C
B
BB
D
test

A
B
BB

$ cat <<test | awk '$1 ~ "A" || $1 ~ "B"'
A
C
B
BB
D
test

A
B
BB

awk -vs1="A" -vs2="B" '$3==s1 || $3==s2 {print}' file_name

awk -vs1="A" -vs2="B" '$3~s1 || $3~s2 {print}' file_name