diff --git a/select b/select
index 7873f9b..5129f1b 100755
--- a/select
+++ b/select
@@ -1,31 +1,37 @@
 #!/bin/bash
+
+md5_source="2cp.md5"
+md5_source_rm="2rm.md5"
+
+md5_aim="aim.md5"
+
 #wenn delete file exits -> handle deletons (importand for konflict handling
-[ -f 2rm.md5 ] && {
-  cat 2rm.md5  | cut -c -32 | while read line; do
-    sed -i "/$line/d" aim.md5
+[ -f "${md5_source_rm}" ] && {
+  cat "${md5_source_rm}"  | cut -c -32 | while read line; do
+    sed -i "/$line/d" "${md5_aim}"
   done
-  cat 2rm.md5  | cut -c 35- | while read line; do
-    l=$(grep "  $line"$ aim.md5)
+  cat "${md5_source_rm}"  | cut -c 35- | while read line; do
+    l=$(grep "  $line"$ "${md5_aim}")
     [ -n "$l" ] && {
       echo $l
       md5=$(echo $l | cut -c -32)
-      sed -i "/$md5/d" aim.md5
+      sed -i "/$md5/d" "${md5_aim}"
     }
   done
-  rm 2rm.md5
+  rm ${md5_source_rm}
 }
 
 #gleiche dateien anhand md5 aussortieren
-cat aim.md5 | cut -c -32 | while read line; do sed -i "/$line/d" 2cp.md5 ; done
+cat "${md5_aim}" | cut -c -32 | while read line; do sed -i "/$line/d" "${md5_source}" ; done
 
 #dateien die verschiedenen md5 haben aber bei beiden existieren als konflikte behandeln
 echo Konflicts:
 echo
-cat aim.md5 | cut -c 35- | while read line; do
-  l=$(grep "  $line"$ 2cp.md5 | tee -a konflicts)
+cat "${md5_aim}" | cut -c 35- | while read line; do
+  l=$(grep "  $line"$ "${md5_source}" | tee -a konflicts)
   [ -n "$l" ] && {
     echo $l
     md5=$(echo $l | cut -c -32)
-    sed -i "/$md5/d" 2cp.md5
+    sed -i "/$md5/d" "${md5_source}"
   }
 done