rem: printf("usage: printenv [VARIABLE]\n"
add: printf("Usage: printenv [VARIABLE]\n"
context: main(int argc, char *argv[]){	char *arg = (argc == 2 ? argv[1] : NULL);		if ((argc > 2) || (arg && !strcmp(arg, "--help"))) {		printf("usage: printenv [VARIABLE]\n"		       "If no environment VARIABLE is specified, print them all.\n");		return 1;	}		return print_env(arg);}