diff --git a/kitty/bash.py b/kitty/bash.py
index 1dad27a1b..320041643 100644
--- a/kitty/bash.py
+++ b/kitty/bash.py
@@ -26,8 +26,6 @@ def ctrl_mask_char(ch: str) -> str:
         o = ord(ch)
     except Exception:
         return ch
-    if o > 127:
-        return ch
     return chr(o & 0b0011111)
 
 
diff --git a/kitty/data-types.c b/kitty/data-types.c
index 9e802c3eb..7886e38c8 100644
--- a/kitty/data-types.c
+++ b/kitty/data-types.c
@@ -233,8 +233,77 @@ wrapped_kittens(PyObject *self UNUSED, PyObject *args UNUSED) {
     return ans;
 }
 
+static PyObject*
+expand_ansi_c_escapes(PyObject *self UNUSED, PyObject *src) {
+    enum { NORMAL, PREV_ESC, HEX_DIGIT, OCT_DIGIT, CONTROL_CHAR } state = NORMAL;
+    if (PyUnicode_READY(src) != 0) return NULL;
+    int max_num_hex_digits = 0, hex_digit_idx = 0;
+    char hex_digits[16];
+    Py_ssize_t idx = 0, dest_idx = 0;
+    PyObject *dest = PyUnicode_New(PyUnicode_GET_LENGTH(src)*2, 1114111);
+    if (dest == NULL) return NULL;
+    const int kind = PyUnicode_KIND(src), dest_kind = PyUnicode_KIND(dest);
+    const void *data = PyUnicode_DATA(src), *dest_data = PyUnicode_DATA(dest);
+#define w(ch) { PyUnicode_WRITE(dest_kind, dest_data, dest_idx, ch); dest_idx++; }
+#define write_digits(base) { hex_digits[hex_digit_idx] = 0; if (hex_digit_idx > 0) w(strtol(hex_digits, NULL, base)); hex_digit_idx = 0; state = NORMAL; }
+#define add_digit(base) { hex_digits[hex_digit_idx++] = ch; if (idx >= PyUnicode_GET_LENGTH(src)) write_digits(base); }
+    START_ALLOW_CASE_RANGE
+    while (idx < PyUnicode_GET_LENGTH(src)) {
+        Py_UCS4 ch = PyUnicode_READ(kind, data, idx); idx++;
+        switch(state) {
+            case NORMAL: {
+                if (ch == '\\' && idx < PyUnicode_GET_LENGTH(src)) {
+                    state = PREV_ESC;
+                    continue;
+                }
+                w(ch);
+            } break;
+            case CONTROL_CHAR: w(ch & 0x1f); state = NORMAL; break;
+            case HEX_DIGIT: {
+                if (hex_digit_idx < max_num_hex_digits && (('0' <= ch && ch <= '9') || ('a' <= ch && ch <= 'f') || ('A' <= ch && ch <= 'F'))) add_digit(16)
+                else { write_digits(16); w(ch); }
+            }; break;
+            case OCT_DIGIT: {
+                if ('0' <= ch && ch <= '7' && hex_digit_idx < max_num_hex_digits) add_digit(16)
+                else { write_digits(8); w(ch); }
+            }; break;
+            case PREV_ESC: {
+                state = NORMAL;
+                switch(ch) {
+                    default: w('\\'); w(ch); break;
+                    case 'a': w(7); break;
+                    case 'b': w(8); break;
+                    case 'c': if (idx < PyUnicode_GET_LENGTH(src)) {state = CONTROL_CHAR;} else {w('\\'); w(ch);}; break;
+                    case 'e': case 'E': w(27); break;
+                    case 'f': w(12); break;
+                    case 'n': w(10); break;
+                    case 'r': w(13); break;
+                    case 't': w(9); break;
+                    case 'v': w(11); break;
+                    case 'x': max_num_hex_digits = 2; hex_digit_idx = 0; state = HEX_DIGIT; break;
+                    case 'u': max_num_hex_digits = 4; hex_digit_idx = 0; state = HEX_DIGIT; break;
+                    case 'U': max_num_hex_digits = 8; hex_digit_idx = 0; state = HEX_DIGIT; break;
+                    case '0' ... '7': max_num_hex_digits = 3; hex_digits[0] = ch; hex_digit_idx = 1; state = OCT_DIGIT; break;
+                    case '\\': w('\\'); break;
+                    case '?': w('?'); break;
+                    case '"': w('"'); break;
+                    case '\'': w('\''); break;
+                }
+            } break;
+        }
+    }
+#undef add_digit
+#undef write_digits
+#undef w
+    END_ALLOW_CASE_RANGE
+    PyObject *ans = PyUnicode_FromKindAndData(dest_kind, dest_data, dest_idx);
+    Py_DECREF(dest);
+    return ans;
+}
+
 static PyMethodDef module_methods[] = {
     {"wcwidth", (PyCFunction)wcwidth_wrap, METH_O, ""},
+    {"expand_ansi_c_escapes", (PyCFunction)expand_ansi_c_escapes, METH_O, ""},
     {"get_docs_ref_map", (PyCFunction)get_docs_ref_map, METH_NOARGS, ""},
     {"getpeereid", (PyCFunction)py_getpeereid, METH_VARARGS, ""},
     {"wcswidth", (PyCFunction)wcswidth_std, METH_O, ""},
diff --git a/kitty/fast_data_types.pyi b/kitty/fast_data_types.pyi
index ab27b4d40..a6a586cbc 100644
--- a/kitty/fast_data_types.pyi
+++ b/kitty/fast_data_types.pyi
@@ -1494,3 +1494,4 @@ def run_with_activation_token(func: Callable[[str], None]) -> None: ...
 def make_x11_window_a_dock_window(x11_window_id: int, strut: Tuple[int, int, int, int, int, int, int, int, int, int, int, int]) -> None: ...
 def unicode_database_version() -> Tuple[int, int, int]: ...
 def wrapped_kittens() -> FrozenSet[str]: ...
+def expand_ansi_c_escapes(test: str) -> str: ...
diff --git a/kitty_tests/datatypes.py b/kitty_tests/datatypes.py
index f1fc9dadb..b45806d1b 100644
--- a/kitty_tests/datatypes.py
+++ b/kitty_tests/datatypes.py
@@ -9,7 +9,7 @@ from kitty.config import build_ansi_color_table, defaults
 from kitty.fast_data_types import (
     Color, ColorProfile, Cursor as C, HistoryBuf, LineBuf,
     parse_input_from_terminal, strip_csi, truncate_point_for_length, wcswidth,
-    wcwidth
+    wcwidth, expand_ansi_c_escapes
 )
 from kitty.rgb import to_color
 from kitty.utils import is_path_in_temp_dir, sanitize_title
@@ -568,3 +568,24 @@ class TestDataTypes(BaseTest):
             self.assertNotIn(b'\x1b[201~', q)
             self.assertNotIn('\x9b201~'.encode('utf-8'), q)
             self.assertIn(b'ab', q)
+
+    def test_expand_ansi_c_escapes(self):
+        for src, expected in {
+            'abc': 'abc',
+            r'a\ab': 'a\ab',
+            r'a\eb': 'a\x1bb',
+            r'a\r\nb': 'a\r\nb',
+            r'a\c b': 'a\0b',
+            r'a\c': 'a\\c',
+            r'a\x1bb': 'a\x1bb',
+            r'a\x1b': 'a\x1b',
+            r'a\x1': 'a\x01',
+            r'a\x1g': 'a\x01g',
+            r'a\z\"': 'a\\z"',
+            r'a\123b': 'a\123b',
+            r'a\128b': 'a\0128b',
+            r'a\u1234e': 'a\u1234e',
+            r'a\U1f1eez': 'a\U0001f1eez',
+        }.items():
+            actual = expand_ansi_c_escapes(src)
+            self.ae(expected, actual)