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