diff --git a/src/util.c b/src/util.c
index 23850ef..d6d7f37 100644
--- a/src/util.c
+++ b/src/util.c
@@ -1,14 +1,99 @@
 #include <string.h>
+#include <stdio.h>
+#include <getopt.h>
 
 #include "util.h"
 #include "../include/yait.h"
 
-// clang-format off
 licence_t TOlicence(const char *s)
 {
-	if (strcmp(s, "mit")) return MIT;
-	if (strcmp(s, "gpl")) return GPL;
-	if (strcmp(s, "bsd")) return BSD;
+	if (strcmp(s, "mit"))
+		return MIT;
+	if (strcmp(s, "gpl"))
+		return GPL;
+	if (strcmp(s, "bsd"))
+		return BSD;
 	return UNL;
 }
-// clang-format on
+
+static char *nextchar;
+
+int getopt_long(int argc, char *const argv[], const char *optstring,
+		const struct option *longopts, int *longindex)
+{
+	if (nextchar == NULL || *nextchar == '\0') {
+		if (optind >= argc)
+			return -1;
+		if (argv[optind][0] != '-' || argv[optind][1] == '\0')
+			return -1;
+		if (argv[optind][1] == '-' && argv[optind][2] == '\0') {
+			optind++;
+			return -1;
+		}
+		if (argv[optind][1] == '-') {
+			const char *arg = argv[optind] + 2;
+			const char *eq = strchr(arg, '=');
+			size_t len = eq ? (size_t)(eq - arg) : strlen(arg);
+			for (int i = 0; longopts[i].name; i++) {
+				if (strncmp(arg, longopts[i].name, len) == 0 &&
+				    strlen(longopts[i].name) == len) {
+					if (longindex)
+						*longindex = i;
+					if (longopts[i].has_arg ==
+					    required_argument) {
+						if (eq)
+							optarg = (char *)eq + 1;
+						else if (optind + 1 < argc)
+							optarg = argv[++optind];
+						else
+							return '?';
+					} else if (longopts[i].has_arg ==
+						   optional_argument)
+						optarg = eq ? (char *)eq + 1 :
+							      NULL;
+					else
+						optarg = NULL;
+					optind++;
+					if (longopts[i].flag) {
+						*longopts[i].flag =
+							longopts[i].val;
+						return 0;
+					}
+					return longopts[i].val;
+				}
+			}
+			optind++;
+			return '?';
+		}
+		nextchar = argv[optind] + 1;
+	}
+	char c = *nextchar++;
+	const char *pos = strchr(optstring, c);
+	if (!pos) {
+		optopt = c;
+		if (*nextchar == '\0')
+			optind++;
+		return '?';
+	}
+	if (pos[1] == ':') {
+		if (*nextchar != '\0') {
+			optarg = nextchar;
+			optind++;
+			nextchar = NULL;
+		} else if (optind + 1 < argc) {
+			optarg = argv[++optind];
+			optind++;
+			nextchar = NULL;
+		} else {
+			optopt = c;
+			return '?';
+		}
+	} else {
+		optarg = NULL;
+		if (*nextchar == '\0') {
+			optind++;
+			nextchar = NULL;
+		}
+	}
+	return c;
+}
diff --git a/src/util.h b/src/util.h
index ec6abec..1fbe065 100644
--- a/src/util.h
+++ b/src/util.h
@@ -5,4 +5,14 @@
 
 licence_t TOlicence(const char *s);
 
+struct option {
+	const char *name;
+	int has_arg;
+	int *flag;
+	int val;
+};
+
+int getopt_long(int argc, char *const argv[], const char *optstring,
+		const struct option *longopts, int *longindex);
+
 #endif