Created SC2036 (markdown)

SC2036.md

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+## If you wanted to assign the output of the pipeline, use a=$(b | c) .
+
+### Problematic code:
+
+    sum=find | wc -l
+
+### Correct code:
+
+    sum=$(find | wc -l)
+
+### Rationale:
+
+The intention in this code was that `sum` would in some way get the value of the command `find | wc -l`.
+
+However, `|` has precedence over the `=`, so the command is a two stage pipeline consisting of `sum=find` and `wc -l`. 
+
+`sum=find` is a plain string assignment. Since it happens by itself in an independent pipeline stage, it has no effect: it produces no output, and the variable disappears when the pipeline stage finishes. Because the assignment produces no output, `wc -l` will count 0 lines.
+
+To instead actually assign a variable with the output of a command, command substitution `$(..)` can be used.
+
+### Exceptions:
+
+None. This warning is triggered whenever the first stage of a pipeline is a single assignment, which is never correct.