add some optional debugging to lip-early.sh

preseed/lip-early.sh

 #!/bin/sh
+
+## ARGS
+IS_DEBUG=0
+
+## SCRIPT
+
+debug() {
+  if [ "$IS_DEBUG" = "1" ]; then
+    "$@"
+  fi
+}
+
 # in earlier releases (but not in kubuntu 22.04), this mount was done automatically
 mkdir -p /root/isodevice
 mount /dev/disk/by-label/LIPSTICK /root/isodevice
@@ -8,6 +20,13 @@ echo "deb [ arch=amd64 trusted=yes ] file:///isodevice/archives-$(sed -n 's/DIST
 echo "deb http://ftp.halifax.rwth-aachen.de/ubuntu/ $(sed -n 's/DISTRIB_CODENAME=\([a-z]\+\)/\1/p' /root/etc/lsb-release) main restricted universe multiverse" >> /root/etc/apt/sources.list
 echo "deb http://ftp.halifax.rwth-aachen.de/ubuntu/ $(sed -n 's/DISTRIB_CODENAME=\([a-z]\+\)/\1/p' /root/etc/lsb-release)-security main restricted universe multiverse" >> /root/etc/apt/sources.list
 echo "deb http://ftp.halifax.rwth-aachen.de/ubuntu/ $(sed -n 's/DISTRIB_CODENAME=\([a-z]\+\)/\1/p' /root/etc/lsb-release)-updates main restricted universe multiverse" >> /root/etc/apt/sources.list
+
+debug echo "As far as I know, there are no logs of anything, which is run in casper. So I sleep here, allowing me to view potential errors ..."
+debug sleep 30
+
 chroot /root /usr/bin/apt-get update
 chroot /root /usr/bin/apt-get -y install $(grep '^[^|#]*L[^|]*|' /root/isodevice/packages | cut -d'|' -f 2)
 sh /root/cdrom/preseed/lipnsa.hook.sh /root/isodevice
+
+debug echo "As far as I know, there are no logs of anything, which is run in casper. So I sleep here, allowing me to view potential errors ..."
+debug sleep 30