#while(){
# Do something with the data here
#}
#__DATA__
# The actual data
#Or you could use the $_ explicitly
#while($_=){
# Do something with the data here
#}
#__DATA__
# The actual data
#Or use another variable instead of $_ as follows:
#while($inputline=){
# Do something with the data here
#}
#__DATA__
# The actual data
while(){
print if /A/; # Print the line if it matches A
}
__DATA__
A
B
I
N
J
K