diff --git a/include/shell.h b/include/shell.h
index 54ff439..3ed875a 100644
--- a/include/shell.h
+++ b/include/shell.h
@@ -1,16 +1,25 @@
 #pragma once
 
-size_t count_args(char *line);
-char **parse_args(char *line, size_t *argc);
-
 struct cmd {
-	const char *key;
-	void (* exec)(const char *line);
+	const char *cmd;
+	const char *desc;
+	void (* exec)(FILE *out, const char **argv, size_t argc);
+};
+
+struct shell {
+	char line[128];
+	struct cmd *cmds;
+	const char *prompt;
+	struct usart_console *con;
+	FILE *fp;
 };
 
-void do_flash_cmd(const char *line);
-void do_ftl_cmd(const char *line);
-void do_mufs_cmd(const char *line);
+size_t count_args(const char *line);
+char **parse_args(const char *line, size_t *argc);
+
+void cmd_exec(struct cmd *cmds, FILE *out, const char **argv, size_t argc);
+void cmd_parse(struct cmd *cmds, FILE *out, const char *line);
 
-void cmd_exec(struct cmd *cmds, const char *line);
-void cmd_loop(const char *s);
+int shell_init(struct shell *shell, struct cmd *cmds,
+	struct usart_console *con, const char *prompt);
+int shell_parse(struct shell *shell);
diff --git a/source/main.c b/source/main.c
index 2bc2795..f28e757 100644
--- a/source/main.c
+++ b/source/main.c
@@ -10,51 +10,43 @@
 #include <libopencm3/stm32/usart.h>
 
 struct usart_console *user_con, *admin_con;
-FILE *user_io, *admin_io;
-char user_line[128];
-char admin_line[128];
+struct shell user_shell, admin_shell;
+
+static void do_echo(FILE *out, const char **argv, size_t argc)
+{
+	if (argc < 1)
+		return;
+
+	fprintf(out, "%s\n", argv[0]);
+}
+
+struct cmd cmds[] = {
+	{ "echo", "", do_echo },
+	{ NULL, NULL, NULL },
+};
 
 int main(void)
 {
-	char **argv;
-	size_t argc, i;
+	FILE *fp;
 
 	rcc_init();
 	gpio_init();
+
 	user_con = console_init(0);
 	admin_con = console_init(1);
-	user_io = console_to_fp(user_con);
-	admin_io = console_to_fp(admin_con);
 
-	fprintf(user_io, "TBM-dev (built on " __DATE__ ")\n");
-	fprintf(admin_io, "TBM-dev (built on " __DATE__ ")\n");
-	fprintf(admin_io, "Welcome to the administrative interface.\n");
-	fprintf(user_io, "tbm # ");
+	fp = console_to_fp(user_con);
+	fprintf(fp, "TBM-dev (built on " __DATE__ ")\n");
 
-	while (1) {
-		if (console_getline(user_con, user_line, 128) == 0) {
-			argv = parse_args(user_line, &argc);
-
-			for (i = 0; i < argc; ++i) {
-				fprintf(user_io, "user: %s\n", argv[i]);
-				fprintf(admin_io, "user: %s\n", argv[i]);
-			}
-
-			free(argv);
-			*user_line = '\0';
-		}
+	fp = console_to_fp(admin_con);
+	fprintf(fp, "TBM-dev (built on " __DATE__ ")\n");
 
-		if (console_getline(admin_con, admin_line, 128) == 0) {
-			argv = parse_args(admin_line, &argc);
+	shell_init(&user_shell, cmds, user_con, "tbm $");
+	shell_init(&admin_shell, cmds, admin_con, "tbm #");
 
-			for (i = 0; i < argc; ++i) {
-				fprintf(admin_io, "admin: %s\n", argv[i]);
-				fprintf(user_io, "admin: %s\n", argv[i]);
-			}
-
-			free(argv);
-			*admin_line = '\0';
-		}
+	while (1) {
+		shell_parse(&user_shell);
+		shell_parse(&admin_shell);
 	}
 
 	return 0;
diff --git a/source/shell/args.c b/source/shell/args.c
index 6fc08bb..66ae3e6 100644
--- a/source/shell/args.c
+++ b/source/shell/args.c
@@ -4,9 +4,9 @@
 
 #include <shell.h>
 
-size_t count_args(char *line)
+size_t count_args(const char *line)
 {
-	char *p = line;
+	const char *p = line;
 	size_t n = 0;
 
 	while (*p != '\0') {
@@ -29,11 +29,11 @@ size_t count_args(char *line)
 	return n;
 }
 
-char **parse_args(char *line, size_t *argc)
+char **parse_args(const char *line, size_t *argc)
 {
 	char **argv;
 	char **arg;
-	char *p = line;
+	const char *p = line;
 	char *s;
 	size_t n;
 
diff --git a/source/shell/cmd.c b/source/shell/cmd.c
index 1f59d98..27d5760 100644
--- a/source/shell/cmd.c
+++ b/source/shell/cmd.c
@@ -2,78 +2,67 @@
 #include <stdlib.h>
 #include <string.h>
 
+#include <console.h>
 #include <shell.h>
 
-static int should_exit = 0;
-static char buf[128];
-static void do_exit(const char *s);
-
-struct cmd main_cmds[] = {
-	{ "exit", do_exit },
-	{ "quit", do_exit },
-	{ "flash", do_flash_cmd },
-	{ "ftl", do_ftl_cmd },
-	{ "mufs", do_mufs_cmd },
-	{ NULL, NULL },
-};
-
-static void do_exit(const char *s)
+void cmd_exec(struct cmd *cmds, FILE *out, const char **argv, size_t argc)
 {
-	(void)s;
+	struct cmd *cmd;
 
-	should_exit = 1;
+	if (argc < 1)
+		return;
+
+	for (cmd = cmds; cmd->cmd; ++cmd) {
+		if (strcmp(cmd->cmd, argv[0]) == 0) {
+			cmd->exec(out, argv + 1, argc - 1);
+			break;
+		}
+	}
 }
 
-static char *prompt(const char *prefix)
+void cmd_parse(struct cmd *cmds, FILE *out, const char *line)
 {
-	size_t len;
-
-	printf(prefix);
-
-	if (!fgets(buf, 128, stdin))
-		return NULL;
-
-	len = strlen(buf);
+	char **argv;
+	size_t argc;
 
-	if (len > 0 && buf[len - 1] == '\n')
-		buf[len - 1] = '\0';
+	if (!(argv = parse_args(line, &argc)))
+		return;
 
-	putchar('\n');
-
-	return buf;
+	cmd_exec(cmds, out, (const char **)argv, argc);
+	free(argv);
 }
 
-void cmd_exec(struct cmd *cmds, const char *line)
+int shell_init(struct shell *shell, struct cmd *cmds,
+	struct usart_console *con, const char *prompt)
 {
-	struct cmd *cmd;
-	const char *args;
-	char *key;
-	size_t n;
+	if (!shell || !con)
+		return -1;
 
-	n = strcspn(line, " \n");
-	key = strndup(line, n);
+	memset(shell->line, '\0', sizeof shell->line);
+	shell->cmds = cmds;
+	shell->con = con;
+	shell->fp = console_to_fp(con);
+	shell->prompt = prompt;
 
-	args = line + n;
-	args += strspn(args, " \n");
+	fprintf(shell->fp, "%s ", prompt ? prompt : "#");
 
-	for (cmd = cmds; cmd->key; ++cmd) {
-		if (strcmp(cmd->key, key) == 0) {
-			cmd->exec(args);
-			break;
-		}
-	}
-
-	free(key);
+	return 0;
 }
 
-void cmd_loop(const char *show)
+int shell_parse(struct shell *shell)
 {
-	char *line;
+	int ret;
 
-	should_exit = 0;
+	if (!shell)
+		return -1;
 
-	while (!should_exit) {
-		line = prompt(show);
-		cmd_exec(main_cmds, line);
-	}
+	if ((ret = console_getline(shell->con, shell->line, sizeof shell->line)) <
+		0)
+		return ret;
+
+	cmd_parse(shell->cmds, shell->fp, shell->line);
+	fprintf(shell->fp, "%s ", shell->prompt ? shell->prompt : "#");
+	*shell->line = '\0';
+
+	return 0;
 }