new file mode 100644
--- /dev/null
+++ b/getopt.c
@@ -0,0 +1,85 @@
+/*
+ * getopt - get option letter from argv
+ *
+ * This is a version of the public domain getopt() implementation by
+ * Henry Spencer, changed for 4.3BSD compatibility (in addition to System V).
+ * It allows rescanning of an option list by setting optind to 0 before
+ * calling, which is why we use it even if the system has its own (in fact,
+ * this one has a unique name so as not to conflict with the system's).
+ * Thanks to Dennis Ferguson for the appropriate modifications.
+ *
+ * This file is in the Public Domain.
+ */
+
+#include <string.h>
+#include <unistd.h>
+
+char	*optarg;	/* Global argument pointer. */
+int	optind = 0;	/* Global argv index. */
+int	opterr = 1;	/* for compatibility, should error be printed? */
+int	optopt;	/* for compatibility, option character checked */
+
+static char	*scan = NULL;	/* Private scan pointer. */
+
+/*
+ * Print message about a bad option.
+ */
+static int badopt(const char *msg, int ch)
+{
+	if (opterr) {
+        write(2, msg, strlen(msg));
+        write(2, &ch, 1);
+        write(2, "\n", 1); 
+	}
+	return ('?');
+}
+
+int getopt(int argc, char *const argv[], const char *optstring)
+{
+	register char c;
+	register const char *place;
+	optarg = NULL;
+
+	if (optind == 0) {
+		scan = NULL;
+		optind++;
+	}
+	
+	if (scan == NULL || *scan == '\0') {
+		if (optind >= argc
+		    || argv[optind][0] != '-'
+		    || argv[optind][1] == '\0') {
+			return (-1);
+		}
+		if (argv[optind][1] == '-'
+		    && argv[optind][2] == '\0') {
+			optind++;
+			return (-1);
+		}
+		scan = argv[optind++]+1;
+	}
+
+	c = *scan++;
+	optopt = c & 0377;
+	for (place = optstring; place != NULL && *place != '\0'; ++place)
+	    if (*place == c)
+		break;
+
+	if (place == NULL || *place == '\0' || c == ':' || c == '?') {
+		return (badopt("getopt: unknown option -", c));
+	}
+
+	place++;
+	if (*place == ':') {
+		if (*scan != '\0') {
+			optarg = scan;
+			scan = NULL;
+		} else if (optind >= argc) {
+			return (badopt("getopt: option requires argument -", c));
+		} else {
+			optarg = argv[optind++];
+		}
+	}
+	return (c & 0377);
+}
+