diff --git a/.github/workflows/directory.jule b/.github/workflows/directory.jule
index ecefa04..18183c4 100644
--- a/.github/workflows/directory.jule
+++ b/.github/workflows/directory.jule
@@ -1,110 +1,145 @@
 use std::process::{exit}
-use std::fs::{FsError, OFlag, open, read_dir}
+use std::fs::{DirEntry, FsError, OFlag, open, read_dir}
 
 static mut TABLE: str = ""
 
 static PACKAGES: [...]str = [
-	"./math",
-	"./search",
-	"./sort",
-	"./string",
+    "./math",
+    "./search",
+    "./sort",
+    "./string",
 ]
 
 fn workflow_failed(message: str) {
-	const FAIL_EXIT_CODE = 1
-	outln(message)
-	exit(FAIL_EXIT_CODE)
+    const FAIL_EXIT_CODE = 1
+    outln(message)
+    exit(FAIL_EXIT_CODE)
 }
 
 fn write(text: str) { TABLE += text }
 fn write_line(text: str) { write(text + "\n") }
 
+fn sort_dirents(mut &dirents: []&DirEntry) {
+    let less = fn(s1: str, s2: str): bool {
+        let s1r = ([]rune)(s1)
+        let s2r = ([]rune)(s2)
+
+        let mut n = s1r.len
+        if n > s2r.len {
+            n = s2r.len
+        }
+
+        let mut i = 0
+        for i < n; i++ {
+            let ir = s1r[i]
+            let jr = s2r[i]
+
+            if ir != jr {
+                ret ir < jr
+            }
+        }
+
+        ret s1r.len < s2r.len
+    }
+
+    let mut i = 0
+    for i < dirents.len-1; i++ {
+        let mut j = 0
+        for j < dirents.len-i-1; j++ {
+            if less(dirents[j+1].name, dirents[j].name) {
+                dirents[j+1], dirents[j] = dirents[j], dirents[j+1]
+            }
+        }
+    }
+}
+
 fn make_name(mut s: str): str {
-	// Remove all cutset substrings.
-	let cutset_subs = [
-		".jule",
-		".",
-		"/",
-		"\\",
-	]
-	for _, subs in cutset_subs {
-		s = s.replace(subs, "", -1)
-	}
-
-	// Replace all underlines with space.
-	s = s.replace("_", " ", -1)
-
-	// Make uppercase first character of all words.
-	let mut i = 0
-	let mut wait_space = false
-	for i < s.len; i++ {
-		let b = s[i]
-		if wait_space {
-			if b == ' ' {
-				wait_space = false
-			}
-			continue
-		}
-
-		s[i] = 'Z' - ('z' - b)
-
-		wait_space = true
-	}
-
-	ret s
+    // Remove all cutset substrings.
+    let cutset_subs = [
+        ".jule",
+        ".",
+        "/",
+        "\\",
+    ]
+    for _, subs in cutset_subs {
+        s = s.replace(subs, "", -1)
+    }
+
+    // Replace all underlines with space.
+    s = s.replace("_", " ", -1)
+
+    // Make uppercase first character of all words.
+    let mut i = 0
+    let mut wait_space = false
+    for i < s.len; i++ {
+        let b = s[i]
+        if wait_space {
+            if b == ' ' {
+                wait_space = false
+            }
+            continue
+        }
+
+        s[i] = 'Z' - ('z' - b)
+
+        wait_space = true
+    }
+
+    ret s
 }
 
 fn append_package(package: str) {
-	let (dirents, err) = read_dir(package)
-	if err != FsError.Ok {
-		workflow_failed("package did not readed: " + package)
-	}
-
-	let package_table_name = make_name(package)
-
-	write_line("")
-	write_line("")
-	write("## ")
-	write(package_table_name)
-	for _, dirent in dirents {
-		// Ignore sub-diretories.
-		if dirent.stat.is_dir() {
-			continue
-		}
-
-		let file_table_name = make_name(dirent.name)
-		let file_url = package + "/" + dirent.name
-
-		write_line("")
-		write("  - [")
-		write(file_table_name)
-		write("](")
-		write(file_url)
-		write(")")
-	}
+    let (mut dirents, err) = read_dir(package)
+    if err != FsError.Ok {
+        workflow_failed("package did not readed: " + package)
+    }
+
+    let package_table_name = make_name(package)
+
+    write_line("")
+    write_line("")
+    write("## ")
+    write(package_table_name)
+    sort_dirents(dirents)
+    for _, dirent in dirents {
+        // Ignore sub-diretories.
+        if dirent.stat.is_dir() {
+            continue
+        }
+
+        let file_table_name = make_name(dirent.name)
+        let file_url = package + "/" + dirent.name
+
+        write_line("")
+        write("  - [")
+        write(file_table_name)
+        write("](")
+        write(file_url)
+        write(")")
+    }
 }
 
 fn create_directory_md() {
-	const MD_PATH = "./DIRECTORY.md"
-	let (mut f, mut err) = open(MD_PATH, OFlag.Rdwr|OFlag.Create|OFlag.Trunc, 0o666)
-	if err != FsError.Ok {
-		workflow_failed("a problem occurs when creating " + MD_PATH)
-	}
-
-	defer { f.close() }
-
-	_, err = f.write(([]byte)(TABLE))
-	if err != FsError.Ok {
-		workflow_failed("a problem occurs when creating " + MD_PATH)
-	}
+    const MD_PATH = "./DIRECTORY.md"
+    let (mut f, mut err) = open(MD_PATH, OFlag.Rdwr|OFlag.Create|OFlag.Trunc, 0o666)
+    if err != FsError.Ok {
+        workflow_failed("a problem occurs when creating " + MD_PATH)
+    }
+
+    defer { f.close() }
+
+    _, err = f.write(([]byte)(TABLE))
+    if err != FsError.Ok {
+        workflow_failed("a problem occurs when creating " + MD_PATH)
+    }
 }
 
 fn main() {
-	write_line("# Table of Contents")
+    write_line("# Table of Contents")
 
-	for _, package in PACKAGES {
-		append_package(package)
-	}
+    for _, package in PACKAGES {
+        append_package(package)
+    }
 
-	create_directory_md()
+    create_directory_md()
 }
diff --git a/DIRECTORY.md b/DIRECTORY.md
index 19f190a..f1ea591 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -2,25 +2,25 @@
 
 
 ## Math
-  - [Median](./math/median.jule)
   - [Abs](./math/abs.jule)
+  - [Median](./math/median.jule)
 
 ## Search
   - [Linear Search](./search/linear_search.jule)
 
 ## Sort
-  - [Shell Sort](./sort/shell_sort.jule)
   - [Bubble Sort](./sort/bubble_sort.jule)
-  - [Selection Sort](./sort/selection_sort.jule)
   - [Exchange Sort](./sort/exchange_sort.jule)
-  - [Quick Sort](./sort/quick_sort.jule)
   - [Insertion Sort](./sort/insertion_sort.jule)
+  - [Quick Sort](./sort/quick_sort.jule)
+  - [Selection Sort](./sort/selection_sort.jule)
+  - [Shell Sort](./sort/shell_sort.jule)
   - [Simple Sort](./sort/simple_sort.jule)
 
 ## String
-  - [Upper Case](./string/upper_case.jule)
-  - [Is Digit](./string/is_digit.jule)
   - [Capitalize](./string/capitalize.jule)
-  - [Lower Case](./string/lower_case.jule)
   - [Is Alpha](./string/is_alpha.jule)
-  - [Reverse](./string/reverse.jule)
\ No newline at end of file
+  - [Is Digit](./string/is_digit.jule)
+  - [Lower Case](./string/lower_case.jule)
+  - [Reverse](./string/reverse.jule)
+  - [Upper Case](./string/upper_case.jule)
\ No newline at end of file