Created SC2120 (markdown)

SC2120.md

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+# foo references arguments, but none are ever passed.
+
+### Problematic code:
+
+    sayhello() {
+      echo "Hello $1"
+    }
+    sayhello
+
+`./myscript World` just prints "Hello " instead of "Hello World".
+
+### Correct code:
+
+    sayhello() {
+      echo "Hello $1"
+    }
+    sayhello "$@"
+
+`./myscript World` now prints "Hello World".
+
+### Rationale:
+
+In a function, `$1` and up refers to the function's parameters, not the script's parameters.
+
+If you want to process your script's parameters in a function, you have to explicitly pass them. You can do this with `myfunction "$@"`. 
+
+Note that `"$@"` refers to the current context's positional parameters, so if you call a function from a function, you have to pass in `"$@"` to both of them:
+
+    first() { second "$@"; }
+    second() { echo "The first script parameter is: $1"; }
+    first "$@"
+
+### Contraindications
+
+If the parameters are optional and you currently just don't want to use them, you can ignore this message.