#include <u.h>#include <libc.h> voidcat(int f, char *s){	char buf[8192];	long n; 	while((n=read(f, buf, (long)sizeof buf))>0)		if(write(1, buf, n)!=n)			sysfatal("write error copying %s: %r", s);	if(n < 0)		sysfatal("error reading %s: %r", s);} voidmain(int argc, char *argv[]){	int f, i; 	argv0 = "cat";	if(argc == 1)		cat(0, "<stdin>");	else for(i=1; i<argc; i++){		f = open(argv[i], OREAD);		if(f < 0)			sysfatal("can't open %s: %r", argv[i]);		else{			cat(f, argv[i]);			close(f);		}	}	exits(0);}