protonvpn-cli: add page (#6255)

pages/linux/protonvpn-cli.md

@@ -0,0 +1,36 @@
+# protonvpn-cli
+
+> Official client for ProtonVPN service from the command-line.
+> More information: <https://github.com/ProtonVPN/linux-cli>.
+
+- Log in to the ProtonVPN account:
+
+`protonvpn-cli login {{username}}`
+
+- Start a kill switch upon connecting to ProtonVPN:
+
+`protonvpn-cli killswitch --on`
+
+- Connect to ProtonVPN interactively:
+
+`protonvpn-cli connect`
+
+- Display connection status:
+
+`protonvpn-cli status`
+
+- Block malware using ProtonVPN NetShield:
+
+`protonvpn-cli netshield --malware`
+
+- Disconnect from ProtonVPN:
+
+`protonvpn-cli disconnect`
+
+- Display the current ProtonVPN configuration:
+
+`protonvpn-cli config --list`
+
+- Display help for a subcommand:
+
+`protonvpn-cli {{subcommand}} --help`