Created SC2053 (markdown)

SC2053.md

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+## Quote the rhs of = in [[ ]] to prevent glob matching.
+
+### Problematic code:
+
+```sh
+[[ $a = $b ]]
+```
+
+### Correct code:
+
+```sh
+[[ $a = "$b" ]]
+```
+### Rationale:
+
+When the right-hand side of `=`, `==` or `!=` is unquoted in `[[ .. ]]`, it will be treated like a glob.
+
+This has some unexpected consequences like `[[ $var = $var ]]` being false (for `var='[a]'`), or `[[ $foo = $bar ]]` giving a different result from `[[ $bar = $foo ]]`.
+
+The most common intention is to compare one variable to another as strings, in which case the right-hand side must be quoted.
+
+### Exceptions:
+
+If you explicitly want to match against a pattern, you can [[ignore]] this warning.