micro-utils/src/echo.c

#include <stdio.h>
#include <ctype.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>

static char n_flag = 0;
static char e_flag = 0;

static void format(char *str) {
	for (size_t i = 0; i < strlen(str); i++) {
		unsigned int c = str[i];
		if (c == '\\') {
			switch (str[i + 1]) {
				case 'a':
					c = '\a';
					break;

				case 'n':
					c = '\n';
					break;

				case 't':
					c = '\t';
					break;

				case 'c':
					exit(0);

				case 'v':
					c = '\v';
					break;

				case 'r':
					c = '\r';
					break;

				case 'f':
					c = '\f';
					break;

				case 'e':
					c = '\033';
					break;

				case 'b':
					c = '\b';
					break;

				default:
					c = '\\';
			}

			i++;
		}

		putchar(c);
	}
}

int main(int argc, char **argv) {

	argv++;
	argc--;

	for (int i = 0; i < argc; i++) {
		if (argv[i][0] == '-') {
			if (strstr(argv[i] + 1, "n"))
				n_flag = 1;

			else if (strstr(argv[i] + 1, "e"))
				e_flag = 1;

			argc--;
			argv++;
		}
	}

	for (int i = 0; i < argc; i++) {
		if (e_flag)
			format(argv[i]);

		else
			fputs(argv[i], stdout);

		if (i < argc - 1)
			putchar(' ');
	}

	if (!n_flag)
		putchar('\n');

	return 0;
}