reimplemented dir2sb and sb2dir to act as 'conversion' utility

Slax/debian/rootcopy/usr/bin/sb2dir

@@ -1,13 +1,33 @@
 #!/bin/bash
-# convert .sb compressed Slax Bundle file into directory tree
 # Author: Tomas M. <http://www.slax.org/>
-#
 
-if [ ! -d "$2" ]; then
+if [ ! -e "$1" ]; then
    echo 
-   echo "Convert .sb compressed module into directory tree"
-   echo "usage: $0 source_file.sb existing_output_directory"
+   echo "Convert .sb compressed module into directory with the same name"
+   echo "usage: $0 [source_file.sb] [[optional output_directory]]"
+   echo "  If the output_directory is specified, it must exist"
+   echo "  If the output_directory is not specified, the name source_file.sb"
+   echo "  is used and the directory is overmounted with tmpfs"
    exit 1
 fi
 
-unsquashfs -f -dest "$2" "$1" >/dev/null
+if [ ! -r "$1" ]; then
+   echo "File does not exist: $1" >&2
+   exit
+fi
+
+if [ "$2" = "" ]; then
+   SOURCE="$1".x
+   while [ -e "$SOURCE" ]; do SOURCE="$SOURCE"x; done
+   mv "$1" "$SOURCE" || exit
+   mkdir "$1"
+   mount -t tmpfs tmpfs "$1"
+   unsquashfs -f -dest "$1" "$SOURCE" >/dev/null || exit
+   rm "$SOURCE"
+else
+   if [ ! -d "$2" ]; then
+      echo "Directory does not exist: $2" >&2
+      exit
+   fi
+   unsquashfs -f -dest "$2" "$1" >/dev/null
+fi