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content/blog/conditional-assignment-bash.md

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+---
+title: "Conditional Assignment in Bash"
+date: 2022-06-19T18:49:47-04:00
+draft: false
+tags: ["Bash"]
+math: false
+---
+
+Many programming languages include an quick way to perform a
+conditional assignment. That is, assigning a variable with a value
+based on some condition. Normally this is done through a ternary
+operator. For example, here is how to write it in Javascript
+
+```javascript
+age = 16;
+ageType = (age > 18) "Adult": "Child";
+```
+The variable `ageType` is dependent upon the value of `age`. If it is above 18 then `ageType = "Adult"` otherwise `ageType = "Child"`.
+
+A more verbose way of accomplishing the same thing is the following:
+```javascript
+if (age > 18) {
+    ageType = "Adult"
+} else {
+    ageType = "Child"
+}
+```
+
+How do we do conditional assignment in Bash? One way is to make use of subshells and echoing out the values.
+
+```bash
+AGE_TYPE=$([ $AGE -gt 18 ] && echo "Adult" || echo "Child")
+```
+A common programming feature called *short-circuiting* makes it
+so that if the first condition (`[ $AGE -gt 18 ]`) is false, then it
+will skip the right side of the AND (`&&`) expression. This is because
+`False && True` is always `False`. However, `False || True` is equal
+to `True`, so the language needs to evaluate the right part of an
+OR (`||`) expression.