Added support for XZ compression

pishrink.sh

@@ -69,6 +69,8 @@ Usage: $0 [-sdrpzh] imagefile.img [newimagefile.img]
   -d: Write debug messages in a debug log file
   -r: Use advanced filesystem repair option if the normal one fails
   -p: Remove logs, apt archives, dhcp leases and ssh hostkeys
+  -x: XZ compress image after shrinking
+  -e: XZ extreme compress image after shrinking
   -z: Gzip compress image after shrinking
 EOM
 	echo "$help"
@@ -82,6 +84,8 @@ usage() {
 	echo "  -d: Debug mode on"
 	echo "  -r: Use advanced repair options"
 	echo "  -p: Remove logs, apt archives, dhcp leases and ssh hostkeys"
+	echo "  -x: XZ compress image after shrinking"
+	echo "  -e: XZ extreme compress image after shrinking"
 	echo "  -z: Gzip compress image after shrinking"
 	echo "  -h: display help text"
 	exit -1
@@ -90,6 +94,8 @@ usage() {
 should_skip_autoexpand=false
 debug=false
 repair=false
+xzip_compress=false
+exzip_compress=false
 gzip_compress=false
 prep=false
 
@@ -99,6 +105,8 @@ while getopts ":sdrpzh" opt; do
     d) debug=true;;
     r) repair=true;;
     p) prep=true;;
+    x) xzip_compress=true;;
+    e) exzip_compress=true;;
     z) gzip_compress=true;;
     h) help;;
     *) usage ;;
@@ -154,7 +162,7 @@ if [ -n "$2" ]; then
   img="$2"
 fi
 
-# cleanup at script exit
+# Cleanup at script exit
 trap cleanup ERR EXIT
 
 #Gather info
@@ -254,7 +262,6 @@ if [[ $prep == true ]]; then
   umount "$mountdir"
 fi
 
-
 # Make sure filesystem is ok
 checkFilesystem
 
@@ -326,6 +333,20 @@ if ! truncate -s "$endresult" "$img"; then
 	exit -16
 fi
 
+if [[ $xzip_compress == true ]]; then
+    info "XZipping the shrunk image"
+    if [[ ! $(xz -9v "$img") ]]; then
+        img=$img.xz
+    fi
+fi
+
+if [[ $exzip_compress == true ]]; then
+    info "Extreme XZipping the shrunk image"
+    if [[ ! $(xz -9ve "$img") ]]; then
+        img=$img.xz
+    fi
+fi
+
 if [[ $gzip_compress == true ]]; then
     info "Gzipping the shrunk image"
     if [[ ! $(gzip -f9 "$img") ]]; then