#include <lib9.h> static voidusage(void){	fprint(2, "usage: mkdir [-p] dir ...\n");	exits("usage");} static intmkdirp(char *s, int pflag){	char *p; 	if(!pflag) {		if(access(s, 0) == 0){			fprint(2, "mkdir: %s already exists\n", s);			exits("exists");		}		return mkdir(s);	} 	/* create intermediate directories */	p = strchr(s+1, '/');	while(p != nil) {		*p = '\0';		if(access(s, 0) != 0 && mkdir(s) != 0)			return -1;		*p = '/';		p = strchr(p+1, '/');	} 	/* create final directory */	if(access(s, 0) == 0)		return 0;	return mkdir(s);} voidmain(int argc, char **argv){	int pflag; 	pflag = 0;	ARGBEGIN{	case 'p':		pflag++;		break;	default:		usage();	}ARGEND	for(; *argv; argv++){		if(mkdirp(*argv, pflag) < 0){			fprint(2, "mkdir: can't create %s\n", *argv);			perror(0);			exits("error");		}	}	exits(0);}