diff --git a/third_party/linenoise/linenoise.c b/third_party/linenoise/linenoise.c
index c49e7b532..3a04e79d4 100644
--- a/third_party/linenoise/linenoise.c
+++ b/third_party/linenoise/linenoise.c
@@ -793,61 +793,63 @@ static char linenoiseGrow(struct linenoiseState *ls, size_t n) {
   return 1;
 }
 
-/* This is an helper function for linenoiseEdit() and is called when the
- * user types the <tab> key in order to complete the string currently in the
- * input.
- *
- * The state of the editing is encapsulated into the pointed linenoiseState
- * structure as described in the structure definition. */
+static size_t linenoiseMaxCompletionLength(linenoiseCompletions *lc) {
+  size_t i, n, m;
+  for (m = i = 0; i < lc->len; ++i) {
+    n = strlen(lc->cvec[i]);
+    m = MAX(n, m);
+  }
+  return m;
+}
+
+/**
+ * Performs tab completion similar in behavior to bash and readline.
+ */
 static ssize_t linenoiseCompleteLine(struct linenoiseState *ls, char *seq,
                                      int size) {
   ssize_t nread;
-  size_t i, n, stop;
+  struct abuf ab;
   linenoiseCompletions lc;
   struct linenoiseState saved;
+  size_t i, j, k, n, perline, itemlen;
+  // we know that the user pressed tab once
   nread = 0;
-  memset(&lc, 0, sizeof(lc));
+  bzero(&lc, sizeof(lc));
   completionCallback(ls->buf, &lc);
-  if (!lc.len) {
-    linenoiseBeep();
-  } else {
-    i = 0;
-    stop = 0;
-    while (!stop) {
-      /* Show completion or original buffer */
-      if (i < lc.len) {
-        saved = *ls;
-        ls->len = ls->pos = strlen(lc.cvec[i]);
-        ls->buf = lc.cvec[i];
-        linenoiseRefreshLine(ls);
-        ls->len = saved.len;
-        ls->pos = saved.pos;
-        ls->buf = saved.buf;
-      } else {
-        linenoiseRefreshLine(ls);
-      }
-      if ((nread = linenoiseRead(ls->ifd, seq, size, ls)) <= 0) {
-        linenoiseFreeCompletions(&lc);
-        return -1;
-      }
-      switch (seq[0]) {
-        case '\t':
-          i = (i + 1) % (lc.len + 1);
-          if (i == lc.len) {
-            linenoiseBeep();
+  if (lc.len == 1) {
+    // if there's a single completion, complete it, and return
+    n = strlen(lc.cvec[0]);
+    if (linenoiseGrow(ls, n + 1)) {
+      memcpy(ls->buf, lc.cvec[0], n + 1);
+      ls->len = ls->pos = n;
+    }
+    linenoiseRefreshLine(ls);
+    nread = linenoiseRead(ls->ifd, seq, size, ls);
+  } else if (lc.len > 1) {
+    // if there's a multiline completions, then do nothing and wait and
+    // see if the user presses tab again. if the user does this we then
+    // print ALL the completions, to above the editing line
+    nread = linenoiseRead(ls->ifd, seq, size, ls);
+    if (nread == 1 && seq[0] == '\t') {
+      itemlen = linenoiseMaxCompletionLength(&lc) + 4;
+      perline = MAX(1, (ls->ws.ws_col - 1) / itemlen);
+      abInit(&ab);
+      abAppends(&ab, "\r\033[K");
+      for (i = 0; i < lc.len;) {
+        for (j = 0; i < lc.len && j < perline; ++j, ++i) {
+          n = GetMonospaceWidth(lc.cvec[i], strlen(lc.cvec[i]), 0);
+          abAppends(&ab, lc.cvec[i]);
+          for (k = n; k < itemlen; ++k) {
+            abAppendw(&ab, ' ');
           }
-          break;
-        default:
-          if (i < lc.len) {
-            n = strlen(lc.cvec[i]);
-            if (linenoiseGrow(ls, n + 1)) {
-              memcpy(ls->buf, lc.cvec[i], n + 1);
-              ls->len = ls->pos = n;
-            }
-          }
-          stop = 1;
-          break;
+        }
+        abAppendw(&ab, READ16LE("\r\n"));
       }
+      ab.len -= 2;
+      abAppends(&ab, "\n");
+      linenoiseWriteStr(ls->ofd, ab.b);
+      linenoiseRefreshLine(ls);
+      abFree(&ab);
     }
   }
   linenoiseFreeCompletions(&lc);
@@ -2074,13 +2076,16 @@ static int linenoiseFallback(const char *prompt, char **res) {
  * @return chomped allocated string of read line or null on eof/error
  */
 char *linenoise(const char *prompt) {
+  bool rm;
   char *res;
   if (linenoiseFallback(prompt, &res)) return res;
   fflush(stdout);
   fflush(stdout);
+  rm = __replmode;
   __replmode = true;
   res = linenoiseRaw(prompt, fileno(stdin), fileno(stdout));
   __replmode = false;
+  __replmode = rm;
   return res;
 }
 
diff --git a/third_party/lua/README.cosmo b/third_party/lua/README.cosmo
index daec0c54e..9cdfdeee5 100644
--- a/third_party/lua/README.cosmo
+++ b/third_party/lua/README.cosmo
@@ -20,9 +20,13 @@ PROVENANCE
 
 LOCAL MODIFICATIONS
 
+  Lua now uses a bestline REPL with bash-style code completion.
+
   Integer literals such as `033` will now be interpreted as octal.
 
   The `\e` string literal escape sequence has been added, which is
   equivalent to `\27` (the Lua version of `\033`) or the ASCII ESC
   character. It may be used for teletypewriter control like having
   bold text, which can be encoded elegantly as `\e[1mHELLO\e[0m`.
+
+  Added luaL_traceback2() for function parameters in traceback.
diff --git a/third_party/lua/lua.main.c b/third_party/lua/lua.main.c
index 51bc6a18c..efb67e72a 100644
--- a/third_party/lua/lua.main.c
+++ b/third_party/lua/lua.main.c
@@ -11,10 +11,11 @@
 #include "libc/calls/struct/sigaction.h"
 #include "libc/dce.h"
 #include "libc/log/log.h"
-#include "libc/runtime/gc.internal.h"
+#include "libc/runtime/gc.h"
 #include "libc/runtime/stack.h"
 #include "libc/sysv/consts/exit.h"
 #include "libc/x/x.h"
+#include "third_party/linenoise/linenoise.h"
 #include "third_party/lua/lauxlib.h"
 #include "third_party/lua/lprefix.h"
 #include "third_party/lua/lua.h"
@@ -378,68 +379,75 @@ static int handle_luainit (lua_State *L) {
 #define LUA_MAXINPUT		512
 #endif
 
+static bool lua_stdin_is_tty(void) {
+  return isatty(0);
+}
 
-/*
-** lua_stdin_is_tty detects whether the standard input is a 'tty' (that
-** is, whether we're running lua interactively).
-*/
-#if !defined(lua_stdin_is_tty)	/* { */
+static bool lua_istartswith(const char *s, const char *prefix) {
+  for (;;) {
+    if (!*prefix) return true;
+    if (!*s) return false;
+    if (tolower(*s++) != tolower(*prefix++)) return false;
+  }
+}
 
-#if defined(LUA_USE_POSIX)	/* { */
+static void lua_readline_addcompletion(linenoiseCompletions *c, char *s) {
+  char **p = c->cvec;
+  size_t n = c->len + 1;
+  if ((p = realloc(p, n * sizeof(*p)))) {
+    p[n - 1] = s;
+    c->cvec = p;
+    c->len = n;
+  }
+}
 
-#define lua_stdin_is_tty()	isatty(0)
+static void lua_readline_completions(const char *p, linenoiseCompletions *c) {
+  lua_State *L;
+  const char *name;
+  L = globalL;
+  lua_pushglobaltable(L);
+  lua_pushnil(L);
+  while (lua_next(L, -2) != 0) {
+    name = lua_tostring(L, -2);
+    if (lua_istartswith(name, p)) {
+      lua_readline_addcompletion(c, strdup(name));
+    }
+    lua_pop(L, 1);
+  }
+  lua_pop(L, 1);
+}
 
-#elif defined(LUA_USE_WINDOWS)	/* }{ */
+static char *lua_readline_hint(const char *p, const char **ansi1, const char **ansi2) {
+  char *h = 0;
+  linenoiseCompletions c = {0};
+  lua_readline_completions(p, &c);
+  if (c.len == 1) h = strdup(c.cvec[0] + strlen(p));
+  linenoiseFreeCompletions(&c);
+  return h;
+}
 
+static void lua_initreadline(lua_State *L) {
+  histpath = xasprintf("%s/.%s_history", _gc(xhomedir()), LUA_PROGNAME);
+  linenoiseSetCompletionCallback(lua_readline_completions);
+  linenoiseSetHintsCallback(lua_readline_hint);
+  linenoiseSetFreeHintsCallback(free);
+}
 
-#define lua_stdin_is_tty()	_isatty(_fileno(stdin))
+static int lua_readline(lua_State *L, char **b, const char *prompt) {
+  globalL = L;
+  linenoiseHistoryLoad(histpath);
+  return !!(*b = linenoise(prompt));
+}
 
-#else				/* }{ */
-
-/* ISO C definition */
-#define lua_stdin_is_tty()	1  /* assume stdin is a tty */
-
-#endif				/* } */
-
-#endif				/* } */
-
-
-/*
-** lua_readline defines how to show a prompt and then read a line from
-** the standard input.
-** lua_saveline defines how to "save" a read line in a "history".
-** lua_freeline defines how to free a line read by lua_readline.
-*/
-#if !defined(lua_readline)	/* { */
-
-#if defined(LUA_USE_READLINE)	/* { */
-
-#define lua_initreadline(L)	((void)L, rl_readline_name="lua")
-#define lua_readline(L,b,p)	((void)L, ((b)=readline(p)) != NULL)
-#define lua_saveline(L,line)	((void)L, add_history(line))
-#define lua_freeline(L,b)	((void)L, free(b))
-
-#elif defined(LUA_USE_LINENOISE)
-#include "third_party/linenoise/linenoise.h"
-
-#define lua_initreadline(L)	(histpath=xasprintf("%s/.%s_history",gc(xhomedir()),LUA_PROGNAME))
-#define lua_readline(L,b,p)	((void)L, linenoiseHistoryLoad(histpath), ((b)=linenoise(p)) != NULL)
-#define lua_saveline(L,line)	((void)L, linenoiseHistoryLoad(histpath), linenoiseHistoryAdd(line), linenoiseHistorySave(histpath))
-#define lua_freeline(L,b)	((void)L, free(b))
-
-#else				/* }{ */
-
-#define lua_initreadline(L)  ((void)L)
-#define lua_readline(L,b,p) \
-        ((void)L, fputs(p, stdout), fflush(stdout),  /* show prompt */ \
-        fgets(b, LUA_MAXINPUT, stdin) != NULL)  /* get line */
-#define lua_saveline(L,line)	{ (void)L; (void)line; }
-#define lua_freeline(L,b)	{ (void)L; (void)b; }
-
-#endif				/* } */
-
-#endif				/* } */
+static void lua_saveline(lua_State *L, const char *line) {
+  linenoiseHistoryLoad(histpath);
+  linenoiseHistoryAdd(line);
+  linenoiseHistorySave(histpath);
+}
 
+static void lua_freeline (lua_State *L, char *b) {
+  free(b);
+}
 
 /*
 ** Return the string to be used as a prompt by the interpreter. Leave
@@ -478,7 +486,6 @@ static int incomplete (lua_State *L, int status) {
   return 0;  /* else... */
 }
 
-
 /*
 ** Prompt the user, read a line, and push it into the Lua stack.
 */
@@ -487,7 +494,7 @@ static int pushline (lua_State *L, int firstline) {
   char *b = buffer;
   size_t l;
   const char *prmt = get_prompt(L, firstline);
-  int readstatus = lua_readline(L, b, prmt);
+  int readstatus = lua_readline(L, &b, prmt);
   if (readstatus == 0)
     return 0;  /* no input (prompt will be popped by caller) */
   lua_pop(L, 1);  /* remove prompt */
@@ -647,6 +654,7 @@ static int pmain (lua_State *L) {
 
 
 int main (int argc, char **argv) {
+  ShowCrashReports();
   int status, result;
   lua_State *L;
   /* if (IsModeDbg()) ShowCrashReports(); */
diff --git a/third_party/lua/lua.mk b/third_party/lua/lua.mk
index 23561cc2b..52934f9b5 100644
--- a/third_party/lua/lua.mk
+++ b/third_party/lua/lua.mk
@@ -31,6 +31,7 @@ THIRD_PARTY_LUA_DIRECTDEPS =							\
 	LIBC_STDIO								\
 	LIBC_STR								\
 	LIBC_SYSV								\
+	LIBC_LOG								\
 	LIBC_TIME								\
 	LIBC_X									\
 	LIBC_TINYMATH								\