From ae5d10bc77d6a4d61d241dea0fd81d955eba4684 Mon Sep 17 00:00:00 2001
From: koalaman <vidar@vidarholen.net>
Date: Sat, 6 Feb 2016 22:53:44 -0800
Subject: [PATCH] Created SC1102 (markdown)

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+## Shells differ in parsing ambiguous $(((. Use spaces: $( (( .
+
+### Problematic code:
+
+```sh
+echo "$((( n > 0)) && mycommand --flags)"
+```
+
+### Correct code:
+
+```sh
+echo "$( (( n > 0)) && mycommand --flags)"
+```
+### Rationale:
+
+You are using `$(((` (or `(((`) to mean `$( ((`: command expansion with an arithmetic command. The more common interpretation is `$(( (`: arithmetic expansion with parentheses. 
+
+This is an ill-defined structure that is parsed differently between different shells and shell versions. Prefer adding a space to make it unambiguous, both to shells and humans.
+
+Consider the `$(((` in `$(((1)) )`:
+
+Ash, dash and Bash 1 parses it as `$(( (` and subsequently fail to find the matching `))`. Zsh and Bash 2+ looks ahead and parses it as `$( ((`. Ksh parses it as `$( ( (`. 
+
+### Exceptions:
+
+None.
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