Created SC2157 (markdown)

SC2157.md

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+## Argument to implicit -n is always true due to literal strings.
+
+### Problematic code:
+
+    if [ "$foo " ]
+    then
+      echo "this is always true"
+    fi
+
+### Correct code:
+
+    if [ "$foo" ]
+    then
+      echo "correctly checks value"
+    fi
+
+### Rationale:
+
+Since `[ str ]` checks that the string is non-empty, the space inside the quotes in the problematic code causes the test to always be true. 
+
+Sometimes this is also caused by overquoting an example, e.g. `[ "$foo -gt 0" ]`, which is always true for the same reason. The intention here was `[ "$foo" -gt 0 ]`.
+
+### Exceptions:
+
+None.