diff --git a/install-debian.sh b/install-debian.sh
old mode 100755
new mode 100644
index 55fd685..1c6ad7c
--- a/install-debian.sh
+++ b/install-debian.sh
@@ -2,8 +2,10 @@
 
 # functions
 function repository {
-    add-apt-repository -y ppa:ultradvorka/ppa
-    add-apt-repository -y ppa:webupd8team/java
+    apt-get install -y software-properties-common && (
+        add-apt-repository -y ppa:ultradvorka/ppa
+        add-apt-repository -y ppa:webupd8team/java
+    )
 }
 
 function update-upgrade {
@@ -13,30 +15,31 @@ function update-upgrade {
 
 function common {
     # default shell
-    apt-get install -y sudo tmux mc tree pv vim mosh bash-completion
+    apt-get install -y sudo mc tree pv vim mosh bash-completion
     
     # bash shell
-    apt-get install -y hh
-    grep HH_CONFIG /etc/bash.bashrc || \
-    hh --show-configuration >> /etc/bash.bashrc
+    apt-get install -y hh && (
+        grep HH_CONFIG /etc/bash.bashrc || \
+            hh --show-configuration >> /etc/bash.bashrc
+    )
     
     # zsh shell
-    apt-get install -y zsh
-    sed 's/\/bin\/bash/\/bin\/zsh/' /etc/passwd > /tmp/passwd
-    mv -f /tmp/passwd /etc/passwd
-    rm -f /tmp/passwd
-    wget -O /etc/zsh/newuser.zshrc.recommended \
-            http://git.grml.org/f/grml-etc-core/etc/zsh/zshrc
-    root_user=$(grep ':0:' /etc/passwd | awk -F':' '{print $6}')
-    default_user=$(grep ':1000:' /etc/passwd | awk -F':' '{print $6}')
-    cp -f /etc/zsh/newuser.zshrc.recommended $default_user/.zshrc
-    cp -f /etc/zsh/newuser.zshrc.recommended $root_user/.zshrc
+    apt-get install -y zsh && (
+        sed -i -- 's/\/bin\/bash/\/bin\/zsh/' /etc/passwd
+        wget -O /etc/zsh/newuser.zshrc.recommended \
+                http://git.grml.org/f/grml-etc-core/etc/zsh/zshrc
+        root_user=$(grep ':0:' /etc/passwd | awk -F':' '{print $6}')
+        default_user=$(grep ':1000:' /etc/passwd | awk -F':' '{print $6}')
+        cp -f /etc/zsh/newuser.zshrc.recommended $default_user/.zshrc
+        cp -f /etc/zsh/newuser.zshrc.recommended $root_user/.zshrc
+    )
     
     # tmux
-    echo 'if [ "$TMUX" = "" ]; then tmux; fi' | cat - $default_user/.zshrc > \
-        /tmp/.zshrc && mv /tmp/.zshrc $default_user/.zshrc
-    echo 'if [ "$TMUX" = "" ]; then tmux; fi' | cat - $root_user/.zshrc > \
-        /tmp/.zshrc && mv /tmp/.zshrc $root_user/.zshrc
+    apt-get install -y tmux && (
+        default_user=$(grep ':1000:' /etc/passwd | awk -F':' '{print $6}')
+        echo 'if [ "$TMUX" = "" ]; then tmux; fi' | cat - $default_user/.zshrc > \
+            /tmp/.zshrc && mv /tmp/.zshrc $default_user/.zshrc
+    )
     
     # diagnostics
     apt-get install -y htop iotop iftop nmon powertop stress lm-sensors \
@@ -46,7 +49,7 @@ function common {
     apt-get install -y git subversion libapache2-svn build-essential
     
     # networking
-    apt-get install -y nfs-common cifs-utils aircrack-ng openvpn axel \
+    apt-get install -y nfs-common cifs-utils openvpn axel \
                        wget ethtool fping 
     
     # misc. tools
@@ -89,8 +92,8 @@ function client-gui {
 }
 
 function client-gui-end {
-  # Java Plugin
-  update-alternatives --config mozilla-javaplugin.so
+    # Java Plugin
+    update-alternatives --config mozilla-javaplugin.so
 }
 
 function server-gui {
@@ -120,8 +123,8 @@ select opt in "${options[@]}"
 do
     case $opt in
         "client-gui")
-            repository
             update-upgrade
+            repository
             common
             client-gui
             common-end
@@ -129,16 +132,16 @@ do
             break
             ;;
         "server-cli")
-            repository
             update-upgrade
+            repository
             common
             server-cli
             common-end
             break
             ;;
         "server-gui")
-            repository
             update-upgrade
+            repository
             common
             server-gui
             common-end