Created SC2143 (markdown)

SC2143.md

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+## Instead of [ -n $(foo | grep bar) ], use  foo | grep -q bar .
+### Problematic code:
+
+    if [ "$(find . | grep 'IMG[0-9]')" ]
+    then
+      echo "Images found"
+    fi
+
+### Correct code:
+
+    if find . | grep -q 'IMG[0-9]'
+    then
+      echo "Images found"
+    fi
+
+### Rationale:
+
+The problematic code has to iterate the entire directory and read all matching lines into memory before making a decision. 
+
+The correct code is cleaner and stops at the first matching line, avoiding both iterating the rest of the directory and reading data into memory.
+
+### Contraindications
+
+None.