Added include for isdigit(); simplified -<num> detection
diff --git a/coreutils/tail.c b/coreutils/tail.c
index 8201c80..024441e 100644
--- a/coreutils/tail.c
+++ b/coreutils/tail.c
@@ -25,6 +25,7 @@
#include <fcntl.h>
#include <getopt.h>
#include <string.h>
+#include <ctype.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
@@ -68,7 +69,7 @@
char *s, *start, *end, buf[BUFSIZ];
int i, opt;
- if (( argc >= 2 ) && ( strlen ( argv [1] ) >= 2 ) && ( argv [1][0] == '-' ) && isdigit ( argv [1][1] )) {
+ if (( argc >= 2 ) && ( argv [1][0] == '-' ) && isdigit ( argv [1][1] )) {
count = atoi ( &argv [1][1] );
optind = 2;
}