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landing/docs/Bash-Scripts/015-writing-your-first-bash-script.md

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+# Your First Bash Script
+
+Time to build your first Bash script. We'll create a script to monitor server status, including:
+* Disk usage
+* CPU load
+* RAM usage (Memory)
+* TCP connections
+* Kernel version
+
+Customize as needed.
+
+### Script Setup
+
+First, create your script file, `status.sh`:
+
+```bash
+touch status.sh
+```
+
+Open `status.sh` with your text editor. Start with the shebang, `#!/usr/bin/env bash`. This tells the system how to execute the script.
+
+Add initial comments for clarity:
+
+```bash
+#!/usr/bin/env bash
+
+# Script to report current server status.
+```
+
+### Variables
+
+Variables store data. Assign values using `=` (no spaces). Use `$()` for command substitution.
+
+Capture the server's hostname:
+
+```bash
+server_name=$(hostname)
+```
+
+Echo the variable to see its value:
+
+```bash
+echo "${server_name}"
+```
+
+### Functions
+
+Functions group commands for reuse. Let's create one for memory usage:
+
+```bash
+function memory_check() {
+    echo ""
+    echo "Memory usage on ${server_name}: "
+    free -h
+    echo ""
+}
+```
+
+This function prints a message and calls `free -h` for memory details. Call it by name (no parentheses):
+
+```bash
+memory_check
+```
+
+Before seeing the complete solution, try implementing functions for:
+* Disk usage
+* CPU load
+* TCP connections
+* Kernel version
+
+Google commands if needed. There are multiple valid approaches.
+
+### The Complete Script
+
+Here's the full `status.sh` script:
+
+```bash
+#!/usr/bin/env bash
+
+##
+# Server status script:
+#   - Memory usage
+#   - CPU load
+#   - TCP connections
+#   - Kernel version
+##
+
+server_name=$(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
+}
+
+all_checks
+```
+
+Save `status.sh`, then make it executable and run:
+
+```bash
+chmod +x status.sh
+./status.sh
+```
+
+### Conclusion
+
+Bash scripting combines Linux commands to automate routine tasks, freeing you for more impactful work. This basic script demonstrates the power of automation.
+
+> {notice} This content was inspired by a piece by softwareshinobi on Dev Team Six.