C script demo application, demoing pipeing input onto two pipes

headtail.c

#!/bin/bash
exc=/tmp/headtail.c
if [ $0 -nt $exc ]; then sed -n "/^\/\*\*$/,\$p" $0 | gcc -x c - -o $exc; fi

cat | $exc

exit
/**
*/
#include <stdio.h>

#define max 1000

int main(int argc, char *argv[])
{
  char line[max+1];
  FILE *pip1 = popen("bash -c \"head -3\"", "w");
  FILE *pip2 = popen("bash -c \"tail -2\"", "w");

  fgets(line, max, stdin);
  while (! feof(stdin))
  {
    fputs(line, pip1);
    fputs(line, pip2);
    fgets(line, max, stdin);
  }

  pclose(pip1);
  pclose(pip2);

  return 0;
}

https://www.raspberrypi.org/forums/viewtopic.php?f=33&t=319473#p1913176

$ echo -e "1\n2\n3\n4\n5\n6\n7" | ./headtail.c 
1
2
3
6
7
$