Add notes on Linux system commands and USB device management

- Added detailed instructions for checking and managing USB devices
- Included commands for:
  - Viewing system information related to USB devices
  - Identifying mount points and device information
  - Checking filesystem and data integrity
  - Testing for bad blocks and running SMART diagnostics
  - Benchmarking read speed and safely removing devices

This commit provides a comprehensive guide for handling USB devices in Linux environments.

notes/linux.md

@@ -0,0 +1,109 @@
+# Linux
+
+## Table of Contents
+
+- [Linux](#linux)
+  - [Table of Contents](#table-of-contents)
+  - [Basic Commands](#basic-commands)
+  - [USB Devices](#usb-devices)
+    - [Test USB Key](#test-usb-key)
+
+## System information
+
+## Basic Commands
+
+## USB Devices
+
+### Test USB Key
+
+**Device Information**
+Check if the system recognizes the device and show the latest system messages related to USB devices being connected.
+
+```bash
+lsusb
+dmesg | tail -n 20
+```
+
+**Find Mount Points and Device Information**
+Identify mount points, partitions, and other relevant details of mounted devices.
+
+```bash
+lsblk -f
+df -h | grep /dev/sdc
+findmnt /dev/sdc1
+mount | grep /dev/sd
+```
+
+**Print Detailed Information About the USB Key**
+View detailed partition and disk information.
+
+```bash
+fdisk -l /dev/sdc
+```
+
+**Test the File System**
+Check and repair the filesystem on the USB key.
+
+```bash
+fsck /dev/sdc1
+```
+
+**Test Data Integrity**
+Perform read/write tests to ensure the integrity of the USB key.
+
+1. **Unmount the USB Key** (if mounted):
+   ```bash
+   umount /media/fabrice/BD48-F8BB
+   ```
+2. **Write Test**:
+   ```bash
+   dd if=/dev/zero of=/dev/sdc bs=4M count=256 status=progress
+   ```
+3. **Read Test**:
+   ```bash
+   dd if=/dev/sdc of=/dev/null bs=4M count=256 status=progress
+   ```
+
+**Check for Bad Blocks**
+Identify any bad sectors on the USB key.
+
+- **Read-only test**:
+  ```bash
+  badblocks -v /dev/sdc
+  ```
+- **Non-destructive read-write test**:
+
+  ```bash
+  badblocks -nsv /dev/sdc
+  ```
+
+- The -n option performs a non-destructive read-write test.
+- The -s option shows progress.
+- The -v option is for verbose output.
+
+**Perform a SMART Test**
+Run SMART diagnostics to test the health of the USB key.
+
+1. **Start a short SMART test**:
+   ```bash
+   smartctl -t short /dev/sdc
+   ```
+2. **View test results**:
+   ```bash
+   smartctl -a /dev/sdc
+   ```
+
+**Benchmark the Speed**
+Measure the read speed of the USB key.
+
+```bash
+hdparm -t /dev/sdc
+```
+
+**Unmount and Safely Remove**
+Unmount the USB key and safely remove it from the system.
+
+```bash
+umount /mnt/usb
+eject /dev/sdc
+```