Minor order of operations changes and var name consistency (lower-case)

sw

@@ -1,23 +1,23 @@
 #!/bin/sh
 # It just swaps two files
 
-export DAISY_INTERNAL=1
+export DAISY_INTERNAL1
 . $(dirname $(realpath $0))/daisy.source
 
-FILE1=$1
-FILE2=$2
+file1=$1
+file2=$2
 
 function helpFn()
 {
-  ERROR=$?
-  if [[ $ERROR -gt 0 ]];
+  error=$?
+  if [[ $error -gt 0 ]];
   then
-    ERROR_TEXT=$(perl -E 'say $!=shift' $ERROR)
-    echo "$DAISY_BIN error ($ERROR): $ERROR_TEXT"
+    error_text=$(perl -E 'say $!=shift' $error)
+    echo "$DAISY_BIN error ($error): $error_text"
   fi
   echo "Usage: $DAISY_BIN <file1> <file2>"
   echo Swap two files in a filesystem.
-  exit $ERROR
+  exit $error
 }
 
 if [[ $@ == *"--help"*  ]];
@@ -36,14 +36,14 @@ trap helpFn ERR
 
 # We want to swap two files
 # Easy, but let's be safe about it
-ls "$FILE1" >/dev/null
-ls "$FILE2" >/dev/null
+ls "$file1" >/dev/null
+ls "$file2" >/dev/null
 
 # Files should exist, now we move
-mv "$FILE1" "$FILE1.sw"
-mv "$FILE2" "$FILE2.sw"
+mv "$file1" "$file1.sw"
+mv "$file2" "$file2.sw"
 
 # We got our moved copies, now we simply rename
-mv "$FILE1.sw" "$FILE2"
-mv "$FILE2.sw" "$FILE1"
+mv "$file1.sw" "$file2"
+mv "$file2.sw" "$file1"