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landing/docs/Bash-Scripts/016-creating-an-interactive-menu-in-bash.md

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+# Interactive Menu
+
+Build interactive Bash menus. This guide shows you how to create a menu where users choose which actions to run, leveraging previously defined functions for server status checks:
+
+* Memory usage
+* CPU load
+* TCP connections
+* Kernel version
+
+Here's the base script containing these functions:
+
+```bash
+#!/usr/bin/env bash
+
+##
+# Server status script:
+#   - Memory usage
+#   - CPU load
+#   - Number of TCP connections
+#   - Kernel version
+##
+
+server_name=$(hostname)
+
+function memory_check() {
+    echo ""
+    echo "Memory usage on ${server_name}: "
+    free -h
+    echo ""
+}
+
+function cpu_check() {
+    echo ""
+    echo "CPU load on ${server_name}: "
+    echo ""
+    uptime
+    echo ""
+}
+
+function tcp_check() {
+    echo ""
+    echo "TCP connections on ${server_name}: "
+    echo ""
+    cat /proc/net/tcp | wc -l
+    echo ""
+}
+
+function kernel_check() {
+    echo ""
+    echo "Kernel version on ${server_name}: "
+    echo ""
+    uname -r
+    echo ""
+}
+
+function all_checks() {
+    memory_check
+    cpu_check
+    tcp_check
+    kernel_check
+}
+```
+
+We'll now integrate this with a menu, allowing users to select a function to execute.
+
+---
+
+### Add Color for Readability
+
+Enhance your menu's readability with simple color functions. Add these variables and functions to your script:
+
+```bash
+##
+# Color Variables
+##
+green='\e[32m'
+blue='\e[34m'
+red='\e[31m'
+clear='\e[0m'
+
+##
+# Color Functions
+##
+
+ColorGreen(){
+    echo -ne $green$1$clear
+}
+ColorBlue(){
+    echo -ne $blue$1$clear
+}
+ColorRed(){
+    echo -ne $red$1$clear
+}
+```
+
+Use them like: `$(ColorBlue 'Your text')`.
+
+---
+
+### Build the Interactive Menu
+
+Create a `menu` function containing the display logic, user input, and a `case` statement for selection.
+
+```bash
+menu(){
+echo -ne "
+My Server Status Menu
+$(ColorGreen '1)') Memory usage
+$(ColorGreen '2)') CPU load
+$(ColorGreen '3)') TCP connections
+$(ColorGreen '4)') Kernel version
+$(ColorGreen '5)') Check All
+$(ColorGreen '0)') Exit
+$(ColorBlue 'Choose an option:') "
+    read -r a
+    case $a in
+        1) memory_check ; menu ;;
+        2) cpu_check ; menu ;;
+        3) tcp_check ; menu ;;
+        4) kernel_check ; menu ;;
+        5) all_checks ; menu ;;
+        0) exit 0 ;;
+        *) echo -e $(ColorRed 'Invalid option.') ; menu ;;
+    esac
+}
+```
+
+Here's how it works:
+* The `echo -ne` block prints the menu options, applying colors.
+* `read -r a` captures user input into variable `a`.
+* The `case` statement executes the corresponding function. After each function, `menu` is called again to display the menu for another choice, creating a loop. `exit 0` handles the exit option.
+
+Finally, call the `menu` function at the end of your script to start the interaction:
+
+```bash
+menu
+```
+
+---
+
+### Complete Script and Testing
+
+Here's the entire script, `menu.sh`, combining all components:
+
+```bash
+#!/usr/bin/env bash
+
+##
+# BASH menu script that checks:
+#   - Memory usage
+#   - CPU load
+#   - Number of TCP connections
+#   - Kernel version
+##
+
+server_name=$(hostname)
+
+function memory_check() {
+    echo ""
+    echo "Memory usage on ${server_name}: "
+    free -h
+    echo ""
+}
+
+function cpu_check() {
+    echo ""
+    echo "CPU load on ${server_name}: "
+    echo ""
+    uptime
+    echo ""
+}
+
+function tcp_check() {
+    echo ""
+    echo "TCP connections on ${server_name}: "
+    echo ""
+    cat /proc/net/tcp | wc -l
+    echo ""
+}
+
+function kernel_check() {
+    echo ""
+    echo "Kernel version on ${server_name}: "
+    echo ""
+    uname -r
+    echo ""
+}
+
+function all_checks() {
+    memory_check
+    cpu_check
+    tcp_check
+    kernel_check
+}
+
+##
+# Color Variables
+##
+green='\e[32m'
+blue='\e[34m'
+red='\e[31m'
+clear='\e[0m'
+
+##
+# Color Functions
+##
+
+ColorGreen(){
+    echo -ne $green$1$clear
+}
+ColorBlue(){
+    echo -ne $blue$1$clear
+}
+ColorRed(){
+    echo -ne $red$1$clear
+}
+
+menu(){
+echo -ne "
+My Server Status Menu
+$(ColorGreen '1)') Memory usage
+$(ColorGreen '2)') CPU load
+$(ColorGreen '3)') TCP connections
+$(ColorGreen '4)') Kernel version
+$(ColorGreen '5)') Check All
+$(ColorGreen '0)') Exit
+$(ColorBlue 'Choose an option:') "
+    read -r a
+    case $a in
+        1) memory_check ; menu ;;
+        2) cpu_check ; menu ;;
+        3) tcp_check ; menu ;;
+        4) kernel_check ; menu ;;
+        5) all_checks ; menu ;;
+        0) exit 0 ;;
+        *) echo -e $(ColorRed 'Invalid option.') ; menu ;;
+    esac
+}
+
+# Call the menu function
+menu
+```
+
+Save this code as `menu.sh`:
+
+```bash
+touch menu.sh
+```
+
+Open `menu.sh` and paste the script. Save and close. Then, make it executable and run:
+
+```bash
+chmod +x menu.sh
+./menu.sh
+```
+
+You'll see the colored menu, prompting for input. Select an option (e.g., `1` for memory check), and the corresponding information will display before the menu reappears, ready for another choice.
+
+---
+
+### Conclusion
+
+You've built an interactive Bash menu, allowing users to effortlessly navigate script functionalities. This enhances user experience for your automation tools.
+
+> {notice} This content was inspired by a piece by softwareshinobi on Dev Team Six.