diff --git a/ulib/linklist.h b/ulib/linklist.h
new file mode 100644
index 0000000..56b07f5
--- /dev/null
+++ b/ulib/linklist.h
@@ -0,0 +1,45 @@
+#ifndef ULIB_LINKLIST_H_
+#define ULIB_LINKLIST_H_
+
+#define LL_APPEND(head, new) \
+  do { \
+    if ((head) != NULL) { \
+      typeof((head)) __tmp; \
+      (new)->next = NULL; \
+      __tmp = (head); \
+      while (__tmp->next != NULL) { \
+        __tmp = __tmp->next; \
+      } \
+      __tmp->next = (new); \
+    } else { \
+      (new)->next = NULL; \
+      (head) = (new); \
+    } \
+  } while(0)
+
+#define LL_REMOVE(head, ele) \
+  do { \
+    typeof((head)) __cur = (head); \
+    typeof((head)) __prev = NULL; \
+    while (__cur != (ele)) { \
+      __prev = __cur; \
+      __cur = __cur->next; \
+    } \
+    if (__prev != NULL) { \
+      __prev->next = __cur->next; \
+    } \
+  } while(0)
+
+#define LL_FINDPROP(head, out, propname, propvalue) \
+  do { \
+    typeof((head)) __tmp = (head); \
+    while (__tmp) { \
+      if (__tmp->propname == (propvalue)) { \
+        (out) = __tmp; \
+        break; \
+      } \
+      __tmp = __tmp->next; \
+    } \
+  } while(0)
+
+#endif // ULIB_LINKLIST_H_
diff --git a/user/tb/interp.c b/user/tb/interp.c
new file mode 100644
index 0000000..87cfc0a
--- /dev/null
+++ b/user/tb/interp.c
@@ -0,0 +1,179 @@
+#include <stddef.h>
+#include <stdbool.h>
+#include <util/util.h>
+#include <string/string.h>
+#include <string/char.h>
+#include <linklist.h>
+#include <dlmalloc/malloc.h>
+#include <uprintf.h>
+#include "interp.h"
+#include "runtime.h"
+
+static InterpResult RES;
+
+void tz_init(Tokenizer *tz, const char *str, size_t len) {
+  tz->str = str;
+  tz->len = len;
+  tz->pos = 0;
+}
+
+void tz_free(Tokenizer *tz) {
+  Token *tk = tz->tokens;
+  while (tk) {
+    Token *tmp = tk;
+    tk = tk->next;
+    dlfree(tmp);
+  }
+}
+
+int tz_next(Tokenizer *tz, Token *out) {
+  while (tz->pos < tz->len && string_chr_isspace(tz->str[tz->pos])) {
+    tz->pos++;
+  }
+
+  if (tz->pos >= tz->len) {
+    return 0;
+  }
+
+  size_t start = tz->pos;
+  if (tz->str[start] == '"') {
+    start++;
+    do {
+      tz->pos++;
+    } while (tz->pos < tz->len && tz->str[tz->pos] != '"');
+    tz->pos++;
+    
+    out->ptr = tz->str + start;
+    out->len = tz->pos - start - 1;
+
+  } else {
+    while (tz->pos < tz->len && !string_chr_isspace(tz->str[tz->pos])) {
+      tz->pos++;
+    }
+    out->ptr = tz->str + start;
+    out->len = tz->pos - start;
+  }
+  
+  return 1;
+}
+
+void tz_classify(Tokenizer *tz) {
+  Token *tk = tz->tokens;
+  while (tk) {
+    if (tk->ptr[0] == '"' && tk->ptr[tk->len - 1] == '"') {
+      tk->type = TOK_STRING;
+    } else {
+      RtCmd *cmd = RTCMDS;
+      while (cmd) {
+        char tmpbuf[0xff] = {0};
+        usnprintf(tmpbuf, sizeof(tmpbuf), "%.*s", (int)tk->len, tk->ptr);
+        if (string_strcmp(tmpbuf, cmd->cmdname) == 0) {
+          tk->type = TOK_CMD;
+          tk->cmd = cmd;
+          break;
+        }
+        cmd = cmd->next;
+      }
+    }
+    tk = tk->next;
+  }
+}
+
+bool interp_readline(char *data, const char **bgptr, const char **endptr) {
+  static char *nextstart;
+  if (data) {
+    nextstart = data;
+    return true;
+  }
+
+  if (*nextstart == '\0') {
+    return false;
+  }
+  *bgptr = nextstart;
+  const char *scn = nextstart;
+
+  for (;;) {
+    while (*scn != '\0' && *scn != '\n') {
+      scn++;
+    }
+    if (*scn == '\n') {
+      if (scn > *bgptr && *(scn - 1) == '\\') {
+        scn--;
+        nextstart = scn;
+        *nextstart = ' ';
+        scn++;
+        if (*scn == '\n') {
+          scn++;
+        }
+        nextstart = scn;
+        continue;
+      }
+    }
+    break;
+  }
+
+  *endptr = scn - 1;
+  
+  while (string_chr_isspace(**bgptr) && *bgptr < *endptr) {
+    (*bgptr)++;
+  }
+
+  while (string_chr_isspace(**endptr) && *endptr >= *bgptr) {
+    (*endptr)--;
+  }
+
+  (*endptr)++;
+
+  if (*scn == '\n') {
+    scn++;
+  }
+  nextstart = scn;
+
+  return true;
+}
+
+bool interp_runstring(const char *string, size_t len, InterpResult **res) {
+  *res = &RES;
+  
+  rt_init();
+  bool ok = true;
+
+  const char *bg, *end;
+  interp_readline((char *)string, NULL, NULL);
+  while (interp_readline(NULL, &bg, &end)) {
+    size_t linelen = end - bg;
+    Tokenizer tz = ZERO(&tz);
+    tz_init(&tz, bg, linelen);
+  
+    Token toktmp = ZERO(&toktmp);
+    while (tz_next(&tz, &toktmp)) {
+      Token *tok = dlmalloc(sizeof(*tok));
+      tok->ptr = toktmp.ptr;
+      tok->len = toktmp.len;
+      LL_APPEND(tz.tokens, tok);
+    }
+  
+    tz_classify(&tz);
+
+    Token *cmdtk = tz.tokens;
+    if (cmdtk->type != TOK_CMD) {
+      ok = false;
+      usprintf(RES.errmsg, "Expected cmd name, but got %.*s", (int)cmdtk->len, cmdtk->ptr);
+      tz_free(&tz);
+      goto done;
+    }
+
+    ok = cmdtk->cmd->fn(cmdtk->next);
+    if (!ok) {
+      ok = false;
+      usprintf(RES.errmsg, "cmd %.*s failed", (int)cmdtk->len, cmdtk->ptr);
+      tz_free(&tz);
+      goto done;
+    }
+
+    tz_free(&tz);
+  }
+
+done:
+  return ok;
+}
diff --git a/user/tb/interp.h b/user/tb/interp.h
new file mode 100644
index 0000000..28cb826
--- /dev/null
+++ b/user/tb/interp.h
@@ -0,0 +1,37 @@
+#ifndef TB_INTERP_H_
+#define TB_INTERP_H_
+
+#include <stddef.h>
+#include <stdbool.h>
+#include "runtime.h"
+
+#define INTERP_ERRMSG_BUF_MAX (2048)
+
+typedef struct {
+  char errmsg[INTERP_ERRMSG_BUF_MAX];
+} InterpResult;
+
+typedef struct Token {
+  struct Token *next;
+  const char *ptr;
+  size_t len;
+
+  enum {
+    TOK_STRING,
+    TOK_CMD,
+  } type;
+
+  struct RtCmd *cmd;
+} Token;
+
+typedef struct {
+  const char *str;
+  size_t len;
+  size_t pos;
+
+  Token *tokens;
+} Tokenizer;
+
+bool interp_runstring(const char *string, size_t len, InterpResult **res);
+
+#endif // TB_INTERP_H_
diff --git a/user/tb/main.c b/user/tb/main.c
index b23bf01..eb76bc4 100644
--- a/user/tb/main.c
+++ b/user/tb/main.c
@@ -13,6 +13,7 @@
 #include <dlmalloc/malloc.h>
 #include <errors.h>
 #include <util/util.h>
+#include "interp.h"
 
 struct {
   char *modestr;
@@ -74,6 +75,14 @@ void do_file(char *filepath) {
     goto done;
   }
 
+  InterpResult *res;
+  bool ok = interp_runstring((const char *)buf, statbuf.size, &res);
+  if (!ok) {
+    uprintf("Interpreter error:\n");
+    uprintf("%s\n", res->errmsg);
+    goto done;
+  }
+
 done:
   dlfree(buf);
   ioctl(ioh, IOCTL_CLOSEF, 0, 0, 0);
diff --git a/user/tb/runtime.c b/user/tb/runtime.c
new file mode 100644
index 0000000..4957b71
--- /dev/null
+++ b/user/tb/runtime.c
@@ -0,0 +1,34 @@
+#include <stddef.h>
+#include <stdbool.h>
+#include <linklist.h>
+#include <dlmalloc/malloc.h>
+#include <uprintf.h>
+#include "runtime.h"
+#include "interp.h"
+
+RtCmd *RTCMDS = NULL;
+
+#define RTCMD(name) \
+  do { \
+    RtCmd *_cmd = dlmalloc(sizeof(*_cmd)); \
+    _cmd->cmdname = #name; \
+    _cmd->fn = rt_##name; \
+    LL_APPEND(RTCMDS, _cmd); \
+  } while(0)
+
+bool rt_print(Token *tks) {
+  Token *tk = tks;
+  while (tk) {
+    uprintf("%.*s", (int)tk->len, tk->ptr);
+    if (tk->next != NULL) {
+      uprintf(" ");
+    }
+    tk = tk->next;
+  }
+
+  return true;
+}
+
+void rt_init(void) {
+  RTCMD(print);
+}
diff --git a/user/tb/runtime.h b/user/tb/runtime.h
new file mode 100644
index 0000000..33fbecd
--- /dev/null
+++ b/user/tb/runtime.h
@@ -0,0 +1,18 @@
+#ifndef TB_RUNTIME_H_
+#define TB_RUNTIME_H_
+
+#include <stdbool.h>
+
+struct Token;
+
+typedef struct RtCmd {
+  struct RtCmd *next;
+  char *cmdname;
+  bool (*fn)(struct Token *tks);
+} RtCmd;
+
+void rt_init(void);
+
+extern RtCmd *RTCMDS;
+
+#endif // TB_RUNTIME_H_