docs: use-dedibackup-ftp-backup: Adding Linux example (scaleway#3928)

Author: QuentinCG

dedibox/dedicated-servers/how-to/use-dedibackup-ftp-backup.mdx

@@ -101,3 +101,51 @@ ABOR, ACCT, APPE, CDUP, CWD, DELE, FEAT, LIST, MDTM, MKD, MODE, NLIST, NOOP, PAS
 In case of a failure during authentication (wrong identifier and/or password), connection failure of the access control list (ACL), or failure of the automatic login from an unauthorized IP, the connection will be systematically terminated with the message **421 Service not available**.
 
 
+### Usage on Linux
+
+To connect to the Dedibackup service, we recommend `lftp` for interactive use and `curl` for automated tasks:
+
+#### Recommended tools
+  * For interactive connections: Use `lftp`, which offers an interface and flexibility suitable for FTP sessions.
+  * For automated scripts: Use `curl` for automation, though some limitations exist with FTP servers that do not support all commands.
+
+#### Example of interactive connection with lftp
+
+For interactive sessions, use `lftp` with the following command:
+```sh
+apt install lftp  # Requirement
+
+FTP_HOST="ftp://dedibackup-dc3.online.net"
+FTP_USER="sd-XXXXX"  # Replace with your server ID or 'auto' for autologin
+FTP_PASS="your_password"  # Leave blank if using autologin
+
+# - Connect to FTP server
+# - Upload a file, list files, remove a file
+# - Disconnect from FTP server
+lftp -u "$FTP_USER,$FTP_PASS" "$FTP_HOST" <<EOF
+# Change to the specified FTP directory
+cd "/"
+# Upload a file
+put "path_to_your_file.7z"
+# List files in the folder
+ls
+# Remove a file
+rm "file_to_remove.7z"
+bye
+EOF
+```
+<Message type="note">
+  Passive mode in `lftp` is automatically managed, so manual configuration is usually unnecessary.
+</Message>
+
+#### Example of automated connection with curl
+When automating tasks, you can use `curl`, though command limitations may apply:
+
+```sh
+# Upload a file
+curl -T "path_to_your_file.7z" -u "sd-XXXXX:your_password" ftp://dedibackup-dc3.online.net/
+```
+<Message type="tip">
+  Replace `dedibackup-dc3` with the actual backup location (`-dc2`, `-dc3`, etc.), as specified in your Dedibox console.
+</Message>
+