/*** Getting and setting environmental variable by command line arguments ***/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define NoArg 1

int main(int argc, char *argv[]){
   char *var, *value;

   if(argc == 1){
      printf(" %s: I need an argument.\n",argv[0]);
      return NoArg;
      }

   if(argc == 2) {
      var   = argv[1];
      value = getenv(var);
      if(value!=NULL)
         printf("$%s=%s\n", var, value);
      else
         printf("$%s has no value\n", var);
      }

   if(argc == 3) {
      char *string;
      var    = argv[1];
      value  = argv[2];
      string = (char*)malloc(strlen(var)+strlen(value)+2);
      strcpy(string,var);
      strcat(string,"=");
      strcat(string,value);
      printf("Calling putenv with: %s\n",string);
      putenv(string);
      free(string);
      }

   return 0;
   }