Introduced option -dummy and enabled real unmounting

xorriso-dd-target/xorriso-dd-target

@@ -60,6 +60,8 @@ print_usage() {
   echo "one advisable device is listed, it really gets overwritten by the"
   echo "file content of the given -image_file. In this case the exit value"
   echo "is zero if writing succeeded, non-zero else."
+  echo "Option -dummy prevents this kind of real action and rather shows the"
+  echo "unmount and write commands on stdout."
   echo
   echo "Options:"
   echo " -list_all          Print list of all found devices with advice, vendor"
@@ -90,7 +92,8 @@ print_usage() {
   echo "                    is found, then they get listed but no writing"
   echo "                    happens. In this case, re-run with one of the"
   echo "                    advised device names to get a real write run."
-  echo
+  echo " -dummy             Report the -DO_WRITE actions but do not perform"
+  echo "                    them."
   echo " -help              Print this text to stdout and then end the program."
   echo "Examples:"
   echo " $0 -with_sudo -list_all"
@@ -119,6 +122,7 @@ reset_job() {
   with_sudo=
   image_file=
   do_write=
+  dummy_run=
 
   # Status
   sudo_cmd=
@@ -173,6 +177,9 @@ arg_interpreter() {
     elif test "$i" = "-image_file"
     then
       next_is="image_file"
+    elif test "$i" = "-dummy"
+    then
+      dummy_run=y
     elif test "$i" = "-DO_WRITE"
     then
       do_write=y
@@ -402,13 +409,16 @@ list_devices() {
 
 write_image() {
 
-  echo "--- not activated yet ---"
-
   if test -z "$umount_cmd"
   then
     echo "No executable program umount found in: $sudo_x_dir_list" >&2
     return 6
   fi
+  if test -n "$dummy_run"
+  then
+    echo "Would do if not -dummy:"
+  fi
+
   partitions=$($lsblk_cmd -n -p -o NAME /dev/"$2" | grep -v '^'/dev/"$2"'$' \
                | sed -e 's/[^a-zA-Z0-9_+@:.,/-]//g' | tr '\n\r' '  ')
   mounted_devs=
@@ -421,17 +431,37 @@ write_image() {
   done
   if test -n "$mounted_devs"
   then
-    echo "Would do:   $sudo_cmd $umount_cmd $mounted_devs"
+    for i in $mounted_devs
+    do
+      if test -n "$dummy_run"
+      then
+        echo "  $sudo_cmd $umount_cmd $i"
+      else
+        if $sudo_cmd $umount_cmd "$i"
+        then
+          echo "Unmounted: $i"
+        else
+          echo "FAILURE: Non-zero exit value with:  sudo_cmd $umount_cmd $i" >&2
+          return 7
         fi
+      fi
+    done
+  fi
+
 
   if test -z "$dd_cmd"
   then
     echo "No executable program dd found in: $sudo_x_dir_list" >&2
     return 6
   fi
-  echo "Would do:   $sudo_cmd $dd_cmd if='${1}' bs=1M of=/dev/${2} ; sync"
-
+  if test -n "$dummy_run"
+  then
+    echo "  $sudo_cmd $dd_cmd if='${1}' bs=1M of=/dev/${2} ; sync"
+  else
     echo "--- not activated yet ---"
+    echo "Would do:   $sudo_cmd $dd_cmd if='${1}' bs=1M of=/dev/${2} ; sync"
+    echo "--- not activated yet ---"
+  fi
 
   return 0
 }