diff --git a/tools/bufr_filter b/tools/bufr_filter
index 6e34b3168..e631b87a0 100755
--- a/tools/bufr_filter
+++ b/tools/bufr_filter
@@ -6,6 +6,7 @@ ECCODES_TOOL=codes_bufr_filter
 result=0 # return code from function
 ERR_TOOL_NOT_FOUND=666
 
+the_tool=$ECCODES_TOOL
 is_emoslib=0
 
 #########################################################
@@ -15,15 +16,12 @@ is_emoslib=0
 #  sets the global variable 'result'
 try_tool()
 {
-    the_tool=$1
-    the_args=$args
-
     if [ -f "${script_dir}/$the_tool" ]; then
-        ${script_dir}/$the_tool $the_args
+        ${script_dir}/$the_tool "${@}"
         result=$?
     else
         if command -v $the_tool >/dev/null 2>&1; then
-            $the_tool $the_args
+            $the_tool "${@}"
             result=$?
         else
             #echo "Could not find $the_tool. Return error"
@@ -36,32 +34,30 @@ try_tool()
 # Deal with case where no arguments are provided e.g. usage
 if [ $# -eq 0 ]; then
     # Give priority to ecCodes over emoslib
-    try_tool $ECCODES_TOOL
+    the_tool=$ECCODES_TOOL
+    try_tool "${@}"
     if [ $result -eq $ERR_TOOL_NOT_FOUND ]; then
-        try_tool $EMOSLIB_TOOL
+        the_tool=$EMOSLIB_TOOL
+        try_tool "${@}"
     fi
     exit 0
 fi
 
 # Now process arguments. The "-i" switch is specific to emoslib
-args="$@"
 for i in "$@" ; do
-   case $i in
-     -i) is_emoslib=1; shift ;;
-     *)  shift ;;
-   esac
+   if [ "$i" = "-i" ]; then is_emoslib=1; fi
 done
 
 #########################################################
 # set -x
 if [ $is_emoslib -eq 1 ]; then
     pkg=emoslib
-    tool=$EMOSLIB_TOOL
-    try_tool $tool
+    the_tool=$EMOSLIB_TOOL
+    try_tool "${@}"
 else
     pkg=ecCodes
-    tool=$ECCODES_TOOL
-    try_tool $tool
+    the_tool=$ECCODES_TOOL
+    try_tool "${@}"
 fi
 if [ $result -eq $ERR_TOOL_NOT_FOUND ]; then
     echo "ERROR: Could not find the executable: $tool. Aborting!"  2>&1