Created SC2128 (markdown)

SC2128.md

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+## Expanding an array without an index only gives the first element.
+
+### Problematic code:
+
+    myarray=(foo bar)
+    for f in $myarray
+    do
+      cat "$f"
+    done
+
+### Correct code:
+
+    myarray=(foo bar)
+    for f in "${myarray[@]}"
+    do
+      cat "$f"
+    done
+
+### Rationale:
+
+When referencing arrays, `$myarray` is equivalent to `${myarray[0]}` -- it results in only the first of multiple elements.
+
+To get all elements as separate parameters, use the index `@` (and make sure to double quote). In the example, `echo "${myarray[@]}"` is equivalent to `echo "foo" "bar"`.
+
+To get all elements as a single parameter, concatenated by the first character in `IFS`, use the index `*`. In the example, `echo "${myarray[*]}"` is equivalent to `echo "foo bar"`.
+
+### Contraindications
+
+None.