Awk + print the second field in the line only if four fields are 0

Question

How to print $ 2 on awk only if the fourth field is not 0 (zero).

line="root     13246 11314  457 15: qsRw -m1"

then awk will print 13246, but if

line="root     13246 11314  0 15: qsRw -m1"

then awk doesn't print anything

Answer 1

awk '{if ($4) print $2;}' < inputfile

Answer 2

awk '$4!=0{print $2}' file

or simply

awk '$4{print $2}' file

The awk syntax is

awk '/pattern/{action}' file

the "template" part is actually an implicit if control. Therefore, you can omit the "if" keyword.