Created SC2159 (markdown)

SC2159.md

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+## [ 0 ] is true. Use 'false' instead
+
+### Problematic code:
+
+    if [ 0 ]
+    then
+      echo "always triggers"
+    fi
+
+### Correct code:
+
+    if false
+    then
+      echo "never triggers"
+    fi
+
+### Rationale:
+
+`[ str ]` checks whether `str` is non-empty. It doesn't matter if `str` is `0`, it will still be evaluated for non-emptyness. 
+
+Instead, use the command `false` which -- as the manual puts it -- does nothing, unsuccessfully.
+
+### Exceptions:
+
+None