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landing/docs/Bash-Scripts/004-bash-variables.md

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+# Variables
+
+Like any language, Bash uses variables. No strict data types here; a variable holds numbers or characters.
+
+Assign a value:
+
+```bash
+name="Shinobi"
+```
+
+> **Note:** No spaces around the `=` sign. This is critical.
+
+Access the value using `$` before the variable name:
+
+```bash
+echo $name
+```
+
+While optional, wrapping the name in curly braces is good practice for clarity:
+
+```bash
+echo ${name}
+```
+
+Both would output: `Shinobi`.
+
+Now, let's build a script.
+
+First, create the file:
+
+```bash
+touch shinobi.sh
+```
+
+Then, open `shinobi.sh` and add this content to include a variable:
+
+```bash
+#!/usr/bin/env bash
+
+name="Shinobi"
+
+echo "Hi there $name"
+```
+
+Save and exit.
+
+Make it executable:
+
+```bash
+chmod +x shinobi.sh
+```
+
+Run your script:
+
+```bash
+./shinobi.sh
+```
+
+You'll see:
+
+```bash
+Hi there Shinobi
+```
+
+This script:
+* `#!/usr/bin/env bash`: Sets the interpreter.
+* `name="Shinobi"`: Defines `name` with its value.
+* `echo "Hi there $name"`: Outputs the welcome message using the variable.
+
+You can use multiple variables:
+
+```bash
+#!/usr/bin/env bash
+
+name="Shinobi"
+greeting="Hello"
+
+echo "$greeting $name"
+```
+
+Save and run `shinobi.sh` again:
+
+```bash
+./shinobi.sh
+```
+
+Output:
+
+```bash
+Hello Shinobi
+```
+
+No semicolons needed at line ends.
+
+### Command Line Parameters
+
+Bash scripts also read variables passed directly from the command line. These are called parameters.
+
+Run your script with inputs like this:
+
+```bash
+./shinobi.sh Troy buddy!
+```
+
+Now, modify your `shinobi.sh` file to access these parameters:
+
+```bash
+#!/usr/bin/env bash
+
+echo "Hello there" $1   # $1: first parameter
+echo "Hello there" $2   # $2: second parameter
+echo "Hello there" $@   # $@: all parameters
+```
+
+The output for `./shinobi.sh Troy buddy!` will be:
+
+```bash
+Hello there Troy
+Hello there buddy!
+Hello there Troy buddy!
+```