patch .bashrc only conditionally

diff --git a/input/howto/dchroot.creole b/input/howto/dchroot.creole
index d2128dc..1f38d61 100644 (file)
--- a/input/howto/dchroot.creole
+++ b/input/howto/dchroot.creole
@@ -26,7 +26,7 @@ chroot $DIST
 echo $DIST > /etc/debian_chroot
 
 # change root's .bashrc:
- patch /root/.bashrc << 'EOF'
+ grep -q debian.chroot /etc/bash.bashrc || patch /root/.bashrc << 'EOF'
 @@ -3,2 +3,6 @@
  export PS1='\h:\w\$ '
 +if [ -e /etc/debian_chroot ]; then