The ARGC and ARGV variables are used to pass arguments to the AWK script from the command line.

ARGC specifies the total number of arguments passed to the AWK script on the command line. It always has a value of 1 or more, as it counts the program name as the first argument.

The AWK script filename specified using the -f option is not counted as an argument. If we declare any variable on the command line, it is counted as an argument in GAWK:

$ awk 'BEGIN { print "No of arguments =", ARGC }' one two three four

The output of the execution of the preceding command is as follows:

No of arguments = 5 

ARGV is an array that stores all the arguments passed to the AWK command, starting from index 0 through to ARGC. ARGV[0] always contains AWK.

In the following example, we show how ARGV and ARGC work. Here, ARGV[0] will store the AWK:

$ vi arguments.awk

BEGIN    {
            print "Total no. of arguments =", ARGC
            for ( i=0; i<ARGC; i++ )
            printf "ARGV[%d] = %s
", i, ARGV[i]
}

$ awk -f arguments.awk a1 a2 a3 a4

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

Total no. of arguments = 5
ARGV[0] = awk
ARGV[1] = a1
ARGV[2] = a2
ARGV[3] = a3
ARGV[4] = a4

The variable assignment using the -v option is also not counted in the command-line argument; however, normal variable assignment is counted in the command-line argument, and is accessible through ARGV. For example:

$ awk -v A=10 -f arguments.awk B=20 one two three

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

Total no. of arguments = 5
ARGV[0] = awk
ARGV[1] = B=20
ARGV[2] = one
ARGV[3] = two
ARGV[4] = three

In the next example, we pass arguments to the script in the format - - argument_name argument_value. The AWK script will accept the employee's first name, empfname, and salary, empsal, as arguments. If we use - - name Amit 4000 as an argument for the AWK script, it will set the salary as 4000 for the employee name Amit as follows:

$ vi argc_argv.awk

BEGIN {
    OFS="	"
    for ( i=0; i<ARGC; i++ )
    {
        if ( ARGV[i]=="--name")
        {
            empfname=ARGV[i+1];
            empsal=ARGV[i+2];
            delete ARGV[i]
            delete ARGV[i+1]
            delete ARGV[i+2]
        }
    }
}
{
if ( $1==empfname)
    print $1,$2,$3,$4,$5,$6,empsal
else
    print $0;
}

$ awk -f argc_argv.awk --name Amit 4000 emp.dat

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

Jack    Singh   9857532312  [email protected]      M   hr      2000
Jane    Kaur    9837432312  [email protected]      F   hr      1800
Eva     Chabra  8827232115  [email protected]       F   lgs     2100
Amit    Sharma    9911887766    [email protected]    M    lgs    4000
Julie   Kapur   8826234556  [email protected]     F   Ops     2500
Ana     Khanna  9856422312  [email protected]    F   Ops     2700
Hari    Singh   8827255666  [email protected]      M   Ops     2350
Victor  Sharma  8826567898  [email protected]    M   Ops     2500
John    Kapur   9911556789  [email protected]      M   hr      2200
Billy   Chabra  9911664321  [email protected]      M   lgs     1900
Sam     khanna  8856345512  [email protected]     F   lgs     2300
Ginny   Singh   9857123466  [email protected]     F   hr      2250
Emily   Kaur    8826175812  [email protected]     F   Ops     2100
Amy     Sharma  9857536898  [email protected]    F   Ops     2500
Vina    Singh   8811776612  [email protected]      F   lgs     230