In this method, we fetch the next input line of the current file into a variable instead of storing it in $0. Its syntax is getline var. The following example illustrates how this method works:

$ vi getline_var.awk

{
    print "$0 ->    : ",NR, $0
    getline tmp;
    print "tmp ->    : ",NR, tmp;
}

$ awk -f getline_var.awk cars.dat

The output of the execution of the previous code is as follows:

$0 ->    :  1 maruti          swift       2007        50000       5
tmp ->   :  2 honda           city        2005        60000       3
$0 ->    :  3 maruti          dezire      2009        3100        6
tmp ->   :  4 chevy           beat        2005        33000       2
$0 ->    :  5 honda           city        2010        33000       6
tmp ->   :  6 chevy           tavera      1999        10000       4
$0 ->    :  7 toyota          corolla     1995        95000       2
tmp ->   :  8 maruti          swift       2009        4100        5
$0 ->    :  9 maruti          esteem      1997        98000       1
tmp ->   :  10 ford            ikon        1995        80000       1
$0 ->    :  11 honda           accord      2000        60000       2
tmp ->   :  12 fiat            punto       2007        45000       3

In the previous example, at the beginning of the body block, before executing any statement, AWK reads the first line from the current input file and stores it in $0. The print statement prints the first line from the current input file. Using the getline command, we force the AWK to read the next line from the current input file and store it in the tmp variable. Then we print the second line stored in the tmp variable. This body block continues to work in the same manner for the rest of the current input file's lines. The $0 will print the odd-numbered line and the tmp variable will print the even-numbered lines of the input file.