diff --git a/bash-5.1/Cargo.toml b/bash-5.1/Cargo.toml
index c97a043982fb4940ac83d2b873095cb9395ff920..aca5602b61b44cfb680059a592d04899c71e340b 100644
--- a/bash-5.1/Cargo.toml
+++ b/bash-5.1/Cargo.toml
@@ -8,7 +8,8 @@ crate-type = ["cdylib"]
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 [workspace]
-members = ["builtins_rust/read", "builtins/command1", "builtins/command2", "builtins_rust/history", "builtins_rust/kill"]
+members = ["builtins_rust/read", "builtins/command1", "builtins/command2", "builtins_rust/history", "builtins_rust/kill",
+"builtins_rust/rlet"]
 
 [dependencies]
 libc = "0.2"
@@ -17,3 +18,4 @@ command2 = {path = "./builtins/command2"}
 read = {path = "./builtins_rust/read"}
 history = {path = "./builtins_rust/history"}
 kill = {path = "./builtins_rust/kill"}
+rlet = {path = "./builtins_rust/rlet"}
diff --git a/bash-5.1/builtins_rust/rlet/Cargo.toml b/bash-5.1/builtins_rust/rlet/Cargo.toml
index e69de29bb2d1d6434b8b29ae775ad8c2e48c5391..dbc2ca83784575b1dfcddd37d226e7b76c722f6e 100644
--- a/bash-5.1/builtins_rust/rlet/Cargo.toml
+++ b/bash-5.1/builtins_rust/rlet/Cargo.toml
@@ -0,0 +1,16 @@
+[package]
+name = "rlet"
+version = "0.1.0"
+edition = "2021"
+authors = ["lvgenggeng"]
+build = "../build.rs"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[lib]
+name = "rlet"
+crate-type = ["cdylib"]
+
+[dependencies]
+libc = "0.2"
+nix = "0.23"
diff --git a/bash-5.1/builtins_rust/rlet/src/intercdep.rs b/bash-5.1/builtins_rust/rlet/src/intercdep.rs
new file mode 100644
index 0000000000000000000000000000000000000000..d2246f94d4f21090d6d6a2aaee70c126f7bd358c
--- /dev/null
+++ b/bash-5.1/builtins_rust/rlet/src/intercdep.rs
@@ -0,0 +1,46 @@
+
+#[repr(C)]
+#[derive(Copy, Clone)]
+pub struct word_desc {
+    pub word: *mut c_char,
+    pub flags: c_int,
+}
+pub type WORD_DESC = word_desc;
+
+#[repr(C)]
+#[derive(Copy, Clone)]
+pub struct word_list {
+    pub next: *mut word_list,
+    pub word: *mut WORD_DESC,
+}
+pub type WORD_LIST = word_list;
+
+pub const EXECUTION_SUCCESS : c_int = 0;
+pub const EXECUTION_FAILURE : c_int = 1;
+pub const EX_USAGE: c_int = 258;
+
+pub const EXP_EXPANDED: c_int = 0x01;
+
+pub type histdata_t = *mut libc::c_void;
+#[repr(C)]
+#[derive(Copy, Clone)]
+pub struct _hist_entry {
+    pub line: *mut c_char,
+    pub timestamp: *mut c_char,
+    pub data: histdata_t,
+}
+pub type HIST_ENTRY = _hist_entry;
+
+extern "C" {
+    pub fn string_list(list: *mut WORD_LIST) -> *mut c_char;
+
+    pub fn builtin_usage();
+    pub fn builtin_help();
+    pub fn builtin_error(format: *const c_char, ...);
+
+    pub fn evalexp (expr: *mut c_char, flags: c_int, validp: *mut c_int) -> c_long;
+
+    pub static mut list_optarg : *mut libc::c_char;
+    pub static mut loptend : *mut WORD_LIST;
+
+}
diff --git a/bash-5.1/builtins_rust/rlet/src/lib.rs b/bash-5.1/builtins_rust/rlet/src/lib.rs
index e69de29bb2d1d6434b8b29ae775ad8c2e48c5391..7fe5af59585a4c068c134779322d1daa71b3d4d5 100644
--- a/bash-5.1/builtins_rust/rlet/src/lib.rs
+++ b/bash-5.1/builtins_rust/rlet/src/lib.rs
@@ -0,0 +1,63 @@
+use std::ffi::CStr;
+use libc::{c_int, c_char, c_long, c_void};
+
+include!(concat!("intercdep.rs"));
+
+#[no_mangle]
+pub extern "C" fn r_let_builtin(mut list: *mut WORD_LIST) -> i32 {
+    println!("r_let_builtin call");
+unsafe {
+    let mut ret: c_long = 0;
+	let mut expok: c_int = 0;
+
+	if !list.is_null() && !(*list).word.is_null() &&
+		libc::strcmp((*((*list).word)).word, "--help\0".as_ptr() as *const c_char) == 0 {
+        builtin_help ();
+        return EX_USAGE;
+    }
+
+	if !list.is_null() && !(*list).word.is_null() && is_option((*((*list).word)).word, b'-') {
+		list = (*list).next;
+    }
+
+	if list.is_null() {
+		builtin_error("expression expected\0".as_ptr() as *mut c_char);
+		return EXECUTION_FAILURE;
+	}
+
+	while !list.is_null() {
+		ret = evalexp((*((*list).word)).word, EXP_EXPANDED, std::mem::transmute(&expok));
+		if expok == 0 {
+			return EXECUTION_FAILURE;
+        }
+        list = (*list).next;
+	}
+
+	return if ret == 0 {EXECUTION_FAILURE} else {EXECUTION_SUCCESS};
+}
+}
+
+#[no_mangle]
+pub extern "C" fn r_exp_builtin(mut list: *mut WORD_LIST) -> i32 {
+    println!("r_exp_builtin call");
+
+unsafe {
+	let mut expok: c_int = 0;
+
+	if list.is_null() {
+		builtin_error("expression expected\0".as_ptr() as *const c_char);
+		return EXECUTION_FAILURE;
+	}
+
+	let exp = string_list(list);
+	let ret = evalexp(exp, EXP_EXPANDED, std::mem::transmute(&expok));
+	libc::free(exp as *mut c_void);
+	return if ret == 0 || expok == 0 {EXECUTION_FAILURE} else {EXECUTION_SUCCESS};
+}
+}
+
+unsafe fn is_option(s: *mut c_char, c: u8) -> bool
+{
+    let str = CStr::from_ptr(s).to_bytes_with_nul();
+    return str[0] == b'-' && str[1] == c && str[2] != 0
+}
\ No newline at end of file
diff --git a/record.txt b/record.txt
index fb8812a9b9c3f8f581af9afe958354b83673a34d..622d73b55363069f0b9cf6028ca6f73447e003da 100644
--- a/record.txt
+++ b/record.txt
@@ -1,3 +1,4 @@
 20
 21
 22
+23