From 9613c75afd4263e1c7e5d3e0f1427b678f01f58a Mon Sep 17 00:00:00 2001
From: Lutz Schwarz <Lutz.Schwarz@vetrontypical.com>
Date: Fri, 4 Sep 2020 11:21:04 +0200
Subject: [PATCH] Option to prepare with hostkeys left untouched

---
 pishrink.sh | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/pishrink.sh b/pishrink.sh
index dbf6b09..2a41147 100755
--- a/pishrink.sh
+++ b/pishrink.sh
@@ -155,7 +155,7 @@ EOF1
 help() {
 	local help
 	read -r -d '' help << EOM
-Usage: $0 [-adhrspvzZ] imagefile.img [newimagefile.img]
+Usage: $0 [-adhrspPvzZ] imagefile.img [newimagefile.img]
 
   -s         Don't expand filesystem when image is booted the first time
   -v         Be verbose
@@ -163,7 +163,8 @@ Usage: $0 [-adhrspvzZ] imagefile.img [newimagefile.img]
   -z         Compress image after shrinking with gzip
   -Z         Compress image after shrinking with xz
   -a         Compress image in parallel using multiple cores
-  -p         Remove logs, apt archives, dhcp leases and ssh hostkeys
+  -p         Remove logs, apt archives, dhcp leases
+  -P         Remove logs, apt archives, dhcp leases and ssh hostkeys
   -d         Write debug messages in a debug log file
 EOM
 	echo "$help"
@@ -176,14 +177,16 @@ repair=false
 parallel=false
 verbose=false
 prep=false
+prep_hostkeys=false
 ziptool=""
 
-while getopts ":adhprsvzZ" opt; do
+while getopts ":adhpPrsvzZ" opt; do
   case "${opt}" in
     a) parallel=true;;
     d) debug=true;;
     h) help;;
     p) prep=true;;
+    P) prep=true; prep_hostkeys=true;;
     r) repair=true;;
     s) should_skip_autoexpand=true ;;
     v) verbose=true;;
@@ -305,10 +308,14 @@ else
 fi
 
 if [[ $prep == true ]]; then
-  info "Syspreping: Removing logs, apt archives, dhcp leases and ssh hostkeys"
+  info "Syspreping: Removing logs, apt archives and dhcp leases"
   mountdir=$(mktemp -d)
   mount "$loopback" "$mountdir"
-  rm -rvf $mountdir/var/cache/apt/archives/* $mountdir/var/lib/dhcpcd5/* $mountdir/var/log/* $mountdir/var/tmp/* $mountdir/tmp/* $mountdir/etc/ssh/*_host_*
+  rm -rvf $mountdir/var/cache/apt/archives/* $mountdir/var/lib/dhcpcd5/* $mountdir/var/log/* $mountdir/var/tmp/* $mountdir/tmp/*
+  if [[ "$prep_hostkeys" == true ]]; then
+    info "Syspreping: Removing ssh hostkeys"
+    rm -rvf $mountdir/etc/ssh/*_host_*
+  fi
   umount "$mountdir"
 fi