update lpic: head,tail,wc doc

Linux/LPIC1/14-head-tail.md

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+# 📘 **Using `head` and `tail` Commands in Linux/Unix**
+
+Both `head` and `tail` are essential commands for viewing specific portions of a file quickly, without opening the entire file.
+
+---
+
+## 🔝 `head` — Show the Top of a File
+
+The `head` command displays the beginning part of a file.
+
+### Syntax
+
+```bash
+head [options] file
+```
+
+### Examples
+
+```bash
+head file1
+```
+
+**Description**:
+Displays the first 10 lines of `file1` (default behavior).
+
+```bash
+head -n 5 file1
+```
+
+**Description**:
+Shows the first 5 lines of `file1`.
+
+---
+
+## 🔚 `tail` — Show the Bottom of a File
+
+The `tail` command displays the end part of a file.
+
+### Syntax
+
+```bash
+tail [options] file
+```
+
+### Examples
+
+```bash
+tail file1
+```
+
+**Description**:
+Displays the last 10 lines of `file1` (default behavior).
+
+```bash
+tail -n 20 file1
+```
+
+**Description**:
+Shows the last 20 lines of `file1`.
+
+```bash
+tail -f file1
+```
+
+**Description**:
+Follows the file as it grows — useful for watching logs in real-time.
+
+---
+
+## ✅ Summary of Options
+
+| Command | Option        | Description                                 |
+| ------- | ------------- | ------------------------------------------- |
+| `head`  | `-n <number>` | Show the first `<number>` lines             |
+| `tail`  | `-n <number>` | Show the last `<number>` lines              |
+| `tail`  | `-f`          | Follow the file in real-time (live updates) |
+

Linux/LPIC1/15-wc.md

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+# 📘 **Using the `wc` Command in Linux/Unix**
+
+`wc` (word count) is a utility that counts lines, words, and bytes or characters in files. It’s useful for quickly getting file size details in text terms.
+
+---
+
+## ⚙️ Syntax
+
+```bash
+wc [option] file
+```
+
+---
+
+## 🔎 Basic Usage
+
+```bash
+wc file
+```
+
+**Example output:**
+
+```
+ 5  6 43 file1
+```
+
+This output means:
+
+| Number | Meaning             |
+| ------ | ------------------- |
+| `5`    | Number of **lines** |
+| `6`    | Number of **words** |
+| `43`   | Number of **bytes** |
+
+---
+
+## 📋 Common Options
+
+| Option | Description               | Example      |
+| ------ | ------------------------- | ------------ |
+| `-l`   | Count **lines** only      | `wc -l file` |
+| `-w`   | Count **words** only      | `wc -w file` |
+| `-c`   | Count **bytes** only      | `wc -c file` |
+| `-m`   | Count **characters** only | `wc -m file` |
+
+---
+
+## 📌 Notes
+
+* `bytes (-c)` counts raw bytes, which might differ from characters (`-m`) in multibyte encodings like UTF-8.
+* Without options, `wc` outputs lines, words, and bytes by default.
+