#include <u.h>#include <libc.h> int	readgid(char *); voidmain(int argc, char *argv[]){	int i;	Dir dir;	char err[ERRLEN];	char *group;	char *errs; 	if(argc < 2){		fprint(2, "usage: chgrp group file ....\n");		exits("usage");	}	group = argv[1];	errs = 0;	for(i=2; i<argc; i++){		if(dirstat(argv[i], &dir)==-1){			errstr(err);			fprint(2, "chgrp: can't stat %s: %s\n", argv[i], err);			errs = "can't stat";			continue;		}		strncpy(dir.gid, group, sizeof(dir.gid));		if(dirwstat(argv[i], &dir)==-1){			errstr(err);			fprint(2, "chgrp: can't wstat %s: %s\n", argv[i], err);			errs = "can't wstat";			continue;		}	}	exits(errs);}