I am writing a C program which determines the number of bytes read from the standard input . I found out there are ways to give input to the program

• piped input
• redirection
• entering into command line while the program is waiting for input

How to find the exact command by which the program was executed from the shell . I tried using command-line arguments but failed .

#include <stdio.h>

int main(int argc,char *argv[])
{
        char buffer[100];
        int n;

        for(n=1;n<argc;n++)
                printf("argument: %s\t",argv[n]);

        printf("\n");
        if(argc==1)
                printf("waiting for input :");
        else if (argc==3)
                printf("Not waiting for input . Got the source from command itself .");

        n = read(0,buffer,100);
        if(n==-1)
                printf("\nError occured in reading");
        printf("\nReading successfully done\n");

        return 0;
}

Also ,