within the Isabelle environment, main executables are always within PATH;

--- a/lib/scripts/getfunctions	Thu Feb 25 18:05:04 2016 +0100
+++ b/lib/scripts/getfunctions	Thu Feb 25 18:08:23 2016 +0100
@@ -28,25 +28,6 @@
   export -f tar
 fi
 
-#main executables
-function isabelle ()
-{
-  "$ISABELLE_TOOL" "$@"
-}
-export -f isabelle
-
-function isabelle_process ()
-{
-  "$ISABELLE_PROCESS" "$@"
-}
-export -f isabelle_process
-
-function isabelle_scala_script ()
-{
-  "$ISABELLE_SCALA_SCRIPT" "$@"
-}
-export -f isabelle_scala_script
-
 #shared library convenience
 function librarypath ()
 {

--- a/lib/scripts/getsettings	Thu Feb 25 18:05:04 2016 +0100
+++ b/lib/scripts/getsettings	Thu Feb 25 18:08:23 2016 +0100
@@ -56,6 +56,7 @@
 ISABELLE_TOOL="$ISABELLE_HOME/bin/isabelle"
 ISABELLE_PROCESS="$ISABELLE_HOME/bin/isabelle_process"
 ISABELLE_SCALA_SCRIPT="$ISABELLE_HOME/bin/isabelle_scala_script"
+PATH="$ISABELLE_HOME/bin:$PATH"
 
 #platform
 source "$ISABELLE_HOME/lib/scripts/isabelle-platform"