diff --git a/src/REAX/Install.sh b/src/REAX/Install.sh
index 0cb94a6b70..2c3aaf2302 100644
--- a/src/REAX/Install.sh
+++ b/src/REAX/Install.sh
@@ -1,5 +1,34 @@
 # Install/unInstall package files in LAMMPS
-# edit 2 Makefile.package files to include/exclude REAX info
+# mode = 0/1/2 for uninstall/install/update
+
+mode=$1
+
+# arg1 = file, arg2 = file it depends on
+
+action () {
+  if (test $mode = 0) then
+    rm -f ../$1
+  elif (! cmp -s $1 ../$1) then
+    if (test -z "$2" || test -e ../$2) then
+      cp $1 ..
+      if (test $mode = 2) then
+        echo "  updating src/$1"
+      fi
+    fi
+  elif (test ! -z "$2") then
+    if (test ! -e ../$2) then
+      rm -f ../$1
+    fi
+  fi
+}
+
+# all package files with no dependencies
+
+for file in *.cpp *.h; do
+  action $file
+done
+
+# edit 2 Makefile.package files to include/exclude package info
 
 if (test $1 = 1) then
 
@@ -21,13 +50,6 @@ include ..\/..\/lib\/reax\/Makefile.lammps
 ' ../Makefile.package.settings
   fi
 
-  cp pair_reax.cpp ..
-  cp pair_reax.h ..
-  cp pair_reax_fortran.h ..
-
-  cp fix_reax_bonds.h ..
-  cp fix_reax_bonds.cpp ..
-
 elif (test $1 = 0) then
 
   if (test -e ../Makefile.package) then
@@ -38,11 +60,4 @@ elif (test $1 = 0) then
     sed -i -e '/^include.*reax.*$/d' ../Makefile.package.settings
   fi
 
-  rm -f ../pair_reax.cpp
-  rm -f ../pair_reax.h
-  rm -f ../pair_reax_fortran.h
-
-  rm -f ../fix_reax_bonds.h
-  rm -f ../fix_reax_bonds.cpp
-
 fi