diff --git a/pre-install.sh b/pre-install.sh
index a9ac5ed..f672177 100644
--- a/pre-install.sh
+++ b/pre-install.sh
@@ -1,10 +1,52 @@
 #!/bin/sh
 
-#upgrade the packages
-apt-get update && apt-get upgrade -y --force-yes
+# Exit codes
+#	1	general error
+#	2	unsupported OS
+#	3	unsupported CPU/OS bits
+#	4	unsupported package manager
 
-#install git
-apt-get install -y --force-yes git
+#try to find and use package manager
+
+#rpm/yum for RHEL, CentOS, Fedora
+which yum && { export pkgmgr='yum' ; export pkgmgr_install=$pkgmgr' -y install' ; export pkgmgr_upgrade_all=$pkgmgr' -y update' ; export pkgmgr_remove=$pkgmgr' -y --nodeps remove' ; }
+
+#rpm/dnf for RHEL 7, CentOS 7, Fedora 23
+which dnf && { export pkgmgr='dnf' ; export pkgmgr_install=$pkgmgr' -y install' ; export pkgmgr_upgrade_all=$pkgmgr' -y upgrade' ; export pkgmgr_remove=$pkgmgr' -y remove' ; }
+
+#?/pacman for Arch
+which pacman && { export pkgmgr='pacman' ; export pkgmgr_install=$pkgmgr' --noconfirm -S' ; export pkgmgr_upgrade_all=$pkgmgr' --noconfirm -Syu' ; export pkgmgr_remove=$pkgmgr' --noconfirm -R' ; }
+
+#portage/emerge for Gentoo
+which emerge && { export pkgmgr='emerge' ; export pkgmgr_install=$pkgmgr' --ask=n' ; export pkgmgr_upgrade_all=$pkgmgr' --ask=n --update --deep --with-bdeps=y @world' ; export pkgmgr_remove=$pkgmgr' --ask=n --unmerge --nodeps' ; }
+
+#?/zypper for SLES/openSUSE
+which zypper && { export pkgmgr='zypper' ; export pkgmgr_install=$pkgmgr' --non-interactive install' ; export pkgmgr_upgrade_all=$pkgmgr' --non-interactive refresh && '$pkgmgr' --non-interactive update' ; export pkgmgr_remove=$pkgmgr' --non-interactive remove' ; }
+
+#dpkg/apt for Debian, Ubuntu
+which apt-get && { export pkgmgr='apt-get' ; export pkgmgr_install=$pkgmgr' -y install' ; export pkgmgr_upgrade_all=$pkgmgr' update && '$pkgmgr' -y --force-yes upgrade' ; export pkgmgr_remove=$pkgmgr' -y remove' ; }
+
+#pkgng/pkg for FreeBSD 10
+which pkg && { export pkgmgr='pkg' ; export pkgmgr_install=$pkgmgr' install --yes' ; export pkgmgr_upgrade_all=$pkgmgr' update && '$pkgmgr' upgrade --yes' ; export pkgmgr_remove=$pkgmgr' delete --yes' ; }
+
+if [ ! -z "$pkgmgr" ]; then
+	#upgrade the packages
+	echo "Info: $pkgmgr_upgrade_all"
+	sh -c "$pkgmgr_upgrade_all"
+
+	#install git
+	echo "Info: $pkgmgr_install git"
+	$pkgmgr_install git
+else
+	echo "Warning: Unsupported package manager"
+fi
+
+#prepare dir
+if [ ! -d /usr/src ]; then
+	mkdir -vp /usr/src
+fi
+
+which git || { echo "Warning: git not found" ; }
 
 #get the install script
 cd /usr/src && git clone https://github.com/fusionpbx/fusionpbx-install.sh.git