linux doc: ip command

Linux/LPIC1/20-ip.md

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+
+# 🌐 IP Command Cheat Sheet
+
+The `ip` command is a powerful tool for network configuration and management in Linux. It replaces many of the older `ifconfig` functionalities.
+
+---
+
+## 📌 General Syntax
+
+```bash
+ip [ OPTIONS ] OBJECT { COMMAND | help }
+```
+
+**Common OBJECTS:**
+
+* `addr` – IP addresses
+* `link` – Network interfaces
+* `route` – Routing tables
+* `neigh` – ARP table
+* `rule`, `netns`, etc.
+
+---
+
+## 🔍 View Network Information
+
+### Show All IP Addresses
+
+```bash
+ip addr show
+# or shorthand:
+ip a
+```
+
+### Show IP for Specific Interface
+
+```bash
+ip addr show dev eth0
+```
+
+### Show Link Layer Information
+
+```bash
+ip link show
+```
+
+---
+
+## 🔧 Interface Management
+
+### Bring Interface Down
+
+```bash
+ip link set eth0 down
+```
+
+### Bring Interface Up
+
+```bash
+ip link set eth0 up
+```
+
+---
+
+## 🌐 IP Address Configuration
+
+### Add an IP Address
+
+```bash
+ip addr add 192.168.1.10/24 dev eth0
+```
+
+### Delete an IP Address
+
+```bash
+ip addr del 192.168.1.10/24 dev eth0
+```
+
+---
+
+## 🛣️ Routing
+
+### Show Routing Table
+
+```bash
+ip route show
+```
+
+### Add a Default Gateway
+
+```bash
+ip route add default via 192.168.1.1
+```
+
+### Add a Specific Route
+
+```bash
+ip route add 192.168.10.0/24 via 192.168.5.2
+```
+
+### Delete a Specific Route
+
+```bash
+ip route del 192.168.10.0/24 via 192.168.5.2
+```
+
+---
+
+## 🧱 Bridge Interface Management
+
+### Create a Bridge
+
+```bash
+ip link add name br0 type bridge
+```
+
+### Delete a Bridge
+
+```bash
+ip link delete br0
+```
+
+### Bring Bridge Up
+
+```bash
+ip link set br0 up
+```
+
+---
+
+## 🛠️ Example: Set a Static IP Address
+
+```bash
+ip link set ens33 up
+ip addr add 10.10.40.12/24 dev ens33
+ip route add default via 10.10.40.1
+```
+
+---
+
+### ✅ Tip:
+
+Always verify with:
+
+```bash
+ip a
+ip r
+```
+