Created SC2144 (markdown)

SC2144.md

@@ -0,0 +1,31 @@
+##  -e doesn't work with globs. Use a for loop.
+
+### Problematic code:
+
+    if [ -e dir/*.mp3 ]
+    then
+      echo "There are mp3 files."
+    fi
+
+### Correct code:
+
+    for file in dir/*.mp3
+    do
+      if [ -e "$file" ]
+      then
+        echo "There are mp3 files"
+        break
+      fi
+    done
+
+### Rationale:
+
+`[ -e file* ]` only works if there's 0 or 1 matches. If there are multiple, it becomes `[ -e file1 file2 ]`, and the test fails. 
+
+`[[ -e file* ]]` doesn't work at all.
+
+Instead, use a for loop to expand the glob and check each result individually.
+
+### Contraindications
+
+None.