Fixed some problems with builder.

Made echo handle escape-sequences.

builder/builder.c

@@ -44,10 +44,14 @@ void Compile(const char *src, const char *output_dir) {
 			exit(1);
 
 		execlp(CC, CC, CFLAGS, src, "-o", path, NULL);
-		kill(getpid(), 9);
+		// kill(getppid(), 9);
+		// Probably doesn't need it as the child is resulted with exit(1)
 
 		/* If compiler return 1 */
 		exit(1);
+	} else if (pid == -1) {
+		fprintf(stderr, "%s", "builder: fork failed");
+		exit(1);
 	}
 
 	free(path);

coreutils/echo.c

@@ -1,16 +1,97 @@
 #include <stdio.h>
+#include <errno.h>
+#include <string.h>
+#include <stdlib.h>
+// I want to perform some sort of hack using errno for flag passing
+
+static char should_stop = 0;
+
+char* ScreenString(const char* str) {
+	size_t len = strlen(str);
+	char* buf = malloc(len + 1);
+	size_t i, buf_idx = 0;
+
+	for(i = 0; i < len - 1; i++) {
+		if (str[i] == '\\') {
+			switch(str[i+1]) {
+				case 'a':
+					buf[buf_idx++] = '\a';
+					break;
+				case 'b':
+					buf[buf_idx++] = '\b';
+					break;
+				case 'c':
+					buf[buf_idx] = '\0';
+					should_stop = 1;
+					return buf;
+				case 'f':
+					buf[buf_idx++] = '\f';
+					break;
+				case 'n':
+					buf[buf_idx++] = '\n';
+					break;
+				case 'r':
+					buf[buf_idx++] = '\r';
+					break;
+				case 't':
+					buf[buf_idx++] = '\t';
+					break;
+				case 'v':
+					buf[buf_idx++] = '\v';
+					break;
+				case '\\':
+					buf[buf_idx++] = '\\';
+					break;
+				case '0':
+					unsigned int c = 0;
+					int offset = 0;
+					if (sscanf(str + i + 1, "%3o%n", &c, &offset)) {
+						buf[buf_idx++] = c;
+						i += offset;
+					}
+					break;
+				default:
+					buf[buf_idx++] = '\\';
+					continue;
+			}
+			i++;
+		} else {
+			buf[buf_idx++] = str[i];
+		}
+	}
+
+	if (i < len) buf[buf_idx] = str[i];
+	errno = 0;
+	return buf;
+}
+
+int main(int argc, const char **argv) {
+	char newline = 1;
 
-int main(const int argc, const char **argv) {
 	if (argc > 1) {
+		if (strcmp(argv[1], "-n") == 0) {
+			newline = 0;
+			argv++;
+			argc--;
+		}
+
 		for (int i = 1; i < argc; i++) {
-			fputs(argv[i], stdout);
+			char* screened = ScreenString(argv[i]);
+			fputs(screened, stdout);
+			free(screened);
+			if (should_stop) return 0;
 			if (i < argc - 1)
 				putchar(' ');
 		}
 	}
-
 	/* https://pubs.opengroup.org/onlinepubs/009604599/utilities/echo.html */
 	/* This version does not support -n option and escape-sequences */
-	putchar('\n');
+	/* https://gist.github.com/fogus/1094067/ */
+	/* It seems like escape sequences are supported only by GNU's one */
+	/* I'd implemented them anyway but you may like not to include them */
+	/* Or to switch them with a flag */
+
+	if (newline)
+		putchar('\n');
 	return 0;
 }