Created SC2284 (markdown)

SC2284.md

@@ -0,0 +1,35 @@
+## Use [ x = y ] to compare values (or quote '==' if literal).
+
+### Problematic code:
+
+```sh
+if $var == value
+then
+  echo "Match"
+fi
+```
+
+### Correct code:
+
+```sh
+if [ "$var" = value ]
+then
+  echo "Match"
+fi
+```
+
+### Rationale:
+
+ShellCheck found an unquoted `==` after a word.
+
+This was most likely supposed to be a comparison, so use square brackets as in the correct code.
+
+### Exceptions:
+
+If the `==` was supposed to be literal, you can quote it to make ShellCheck ignore it:
+
+    grep '===' file.js
+
+### Related resources:
+
+* Help by adding links to BashFAQ, StackOverflow, man pages, POSIX, etc!