getopt

tee.c

@@ -2,29 +2,35 @@
 #include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include <string.h>
+#include <unistd.h>
 #include "util.h"
 
 int
 main(int argc, char *argv[])
 {
 	bool aflag = false;
-	char buf[BUFSIZ];
+	char buf[BUFSIZ], c;
 	int i, nfps = 1;
 	size_t n;
 	FILE **fps;
 
-	if(argc > 1 && !strcmp(argv[1], "-a"))
-		aflag = true;
+	while((c = getopt(argc, argv, "a")) != -1)
+		switch(c) {
+		case 'a':
+			aflag = true;
+			break;
+		default:
+			exit(EXIT_FAILURE);
+		}
 	if(!(fps = malloc(sizeof *fps)))
 		eprintf("malloc:");
 	fps[nfps-1] = stdout;
 
-	for(i = aflag ? 2 : 1; i < argc; i++) {
+	for(; optind < argc; optind++) {
 		if(!(fps = realloc(fps, ++nfps * sizeof *fps)))
 			eprintf("realloc:");
-		if(!(fps[nfps-1] = fopen(argv[i], aflag ? "a" : "w")))
-			eprintf("fopen %s:", argv[i]);
+		if(!(fps[nfps-1] = fopen(argv[optind], aflag ? "a" : "w")))
+			eprintf("fopen %s:", argv[optind]);
 	}
 	while((n = fread(buf, 1, sizeof buf, stdin)) > 0)
 		for(i = 0; i < nfps; i++)