diff --git a/tools/install/create_clean_fpcsrc_directory.sh b/tools/install/create_clean_fpcsrc_directory.sh
index 69622ae1d4..05359c3b6f 100755
--- a/tools/install/create_clean_fpcsrc_directory.sh
+++ b/tools/install/create_clean_fpcsrc_directory.sh
@@ -53,7 +53,7 @@ find . -name "CVS" -exec rm -rf {} \;
 # delete all .svn directories
 find . -name ".svn" -exec rm -rf {} \;
 # delete all executables
-find . -perm +a+x -type f -exec rm -f {} \;
+find . -perm /a+x -type f -exec rm -f {} \;
 cd -
 
 # end.
diff --git a/tools/install/create_clean_lazarus_directory.sh b/tools/install/create_clean_lazarus_directory.sh
index 80956ce3ff..8433080386 100755
--- a/tools/install/create_clean_lazarus_directory.sh
+++ b/tools/install/create_clean_lazarus_directory.sh
@@ -55,7 +55,7 @@ find . -name "CVS" -exec rm -rf {} \;
 # delete all SVN directories
 find . -name ".svn" -exec rm -rf {} \;
 # delete all executables
-find . -perm +a+x -type f -exec rm -f {} \;
+find . -perm /a+x -type f -exec rm -f {} \;
 rm -rf tools/install/*.tgz
 rm -rf tools/install/*.*.spec
 cd -
diff --git a/tools/install/macosx/create_lazarus_dmg.sh b/tools/install/macosx/create_lazarus_dmg.sh
index 8b04edfc47..52ff17b7d2 100755
--- a/tools/install/macosx/create_lazarus_dmg.sh
+++ b/tools/install/macosx/create_lazarus_dmg.sh
@@ -168,7 +168,7 @@ ln -s /Developer/lazarus/lazarus.app $ROOTDIR/Applications/Lazarus.app
 # everyone can read, group can write
 find $BUILDDIR -exec chmod a+r,g+w {} \;
 # what is executable should be executable by everyone
-find $BUILDDIR -perm +o+x -exec chmod a+x {} \;
+find $BUILDDIR -perm /o+x -exec chmod a+x {} \;
 # everyone can access directories
 find $BUILDDIR -type d -exec chmod a+x {} \;