diff --git a/__log/fern/Cargo.lock b/__log/fern/Cargo.lock
new file mode 100644
index 0000000..7886245
--- /dev/null
+++ b/__log/fern/Cargo.lock
@@ -0,0 +1,117 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "autocfg"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
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+dependencies = [
+ "libc",
+ "num-integer",
+ "num-traits",
+ "time",
+ "winapi",
+]
+
+[[package]]
+name = "fern"
+version = "0.1.0"
+dependencies = [
+ "chrono",
+ "fern 0.6.0",
+ "log",
+]
+
+[[package]]
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+ "log",
+]
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+ "num-traits",
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+ "autocfg",
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+ "libc",
+ "wasi",
+ "winapi",
+]
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+ "winapi-i686-pc-windows-gnu",
+ "winapi-x86_64-pc-windows-gnu",
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+[[package]]
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diff --git a/__log/fern/Cargo.toml b/__log/fern/Cargo.toml
new file mode 100644
index 0000000..4405f42
--- /dev/null
+++ b/__log/fern/Cargo.toml
@@ -0,0 +1,12 @@
+[package]
+name = "fern"
+version = "0.1.0"
+authors = ["Hatter Jiang <jht5945@gmail.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+log = "0.4.11"
+fern = "0.6.0"
+chrono = "0.4.19"
diff --git a/__log/fern/src/main.rs b/__log/fern/src/main.rs
new file mode 100644
index 0000000..9ff4b48
--- /dev/null
+++ b/__log/fern/src/main.rs
@@ -0,0 +1,25 @@
+#[macro_use] extern crate log;
+
+use log::warn;
+
+fn main() {
+    fern::Dispatch::new()
+    .format(|out, message, record| {
+        out.finish(format_args!(
+            "{}[{}][{}] {}",
+            chrono::Local::now().format("[%Y-%m-%d][%H:%M:%S]"),
+            record.target(),
+            record.level(),
+            message
+        ))
+    })
+    .level(log::LevelFilter::Debug)
+    // .level_for(module, level)
+    .chain(std::io::stdout())
+    .apply().unwrap();
+
+    debug!("Hello, world!");
+    info!("Hello, world!");
+    warn!("Hello, world!");
+    error!("Hello, world!");
+}