makemod: add interactive mode (-i switch) to prevent overwriting module file.

Default behaviour of makemod is to overwrite the destination squashfs module
without asking.  When adding the '-i' switch to the 'makemod' command,
the script will ask explicitly whether it is allowed to overwrite an
existing file.
Also added is a '-h' switch which shows help on using the script.
Bugfix: add "-noappend" to the squashfs command in the script to avoid
adding new data to an existing squashfs module.

1 files changed, 55 insertions, 3 deletions

diff --git a/makemod b/makemod
index 4cc9c26..27ba575 100755
--- a/makemod
+++ b/makemod
@@ -2,10 +2,62 @@
 # Create squashfs module from a directory or a Slackware package.
 # Module can then be added to liveslak/addons directory.
 
+# By default, overwrite destination module file without asking if it pre-exists.
+INTERACTIVE=NO
+
+function help() {
+  cat <<EOH
+
+-- Usage:
+   $(basename $0) [-i] <packagename|directory> modulename.sxz
+-- Option parameters:
+   h :    This help.
+   i :    Interactive mode will not overwrite destination file by default.
+-- Description:
+   The first parameter is either the full path to a Slackware package,
+   or else a directory.
+   If a packagename is supplied as first parameter, it will be installed
+   into a temporary directory using Slackware's "installpkg".
+   The content of the temporary directory will be squashed into a module
+   by the "squashfs" program.
+   If a directoryname is supplied, its content will be squashed into
+   a module by the "squashfs" program.
+   The second parameter is the full pathname of the output module
+   which will be created.
+
+EOH
+}
+
+# Option parsing:
+while getopts "hi" Option
+do
+  case $Option in
+    h ) help; exit
+        ;;
+    i ) INTERACTIVE="YES"
+        ;;
+    * ) help; exit
+        ;;   # DEFAULT
+  esac
+done
+shift $(($OPTIND - 1))
+# End of option parsing.
+#  $1 now references the first non option item supplied on the command line
+# ---------------------------------------------------------------------------
+
+# Input check:
 if [ "x$1" = "x" ]; then
-   echo "-- Usage:"
-   echo "   $(basename $0) <packagename|directory> modulename.sxz"
+   help
+   exit 1
+elif [ "x$2" = "x" ]; then
+   help
    exit 1
+elif [ -f "$2" -a "$INTERACTIVE" = "YES" ]; then
+  read -p "-- Destination file '$2' already exists. Overwrite Y/N (y): " ANSWER
+  if [ "x$ANSWER" = "xN" -o "x$ANSWER" = "xn" ]; then
+    echo "-- Aborting now."
+    exit
+  fi
 fi
 
 # .sxz extension uses xz compression:
@@ -37,7 +89,7 @@ else
   fi
 fi
 
-mksquashfs "${PKGDIR}" "$2" -comp ${COMPR} -b 256K $3 $4 $5 $6 $7 $8 $9
+mksquashfs "${PKGDIR}" "$2" -noappend -comp ${COMPR} -b 256K $3 $4 $5 $6 $7 $8 $9
 if [ $? -ne 0 ]; then
   echo "-- Error creating squashfs compressed module"
   exit 1