LHa self-extracting archive to .lzh archive converter.

deSFX.sh

#!/usr/bin/env bash
# Copyright (c) 2013 Koichi OKADA. All rights reserved.
# This script is distributed under the MIT license.
# http://www.opensource.org/licenses/mit-license.php

if [ "$1" = "" ]; then
  echo "LHa self-extracting archive to .lzh archive converter."
  echo "Usage: ${0##*/} file ..."
  echo
  exit 1
fi

while [ "$1" != "" ]; do
  file "$1" | grep -q "LHa self-extracting archive"
  if [ "$?" = "0" ]; then
    ARCHIVE="${1%.*}.lzh"
    if [ -e "$ARCHIVE" ]; then
      echo "$ARCHIVE: already exists."
    else
      echo "deSFX: $ARCHIVE"
      SKIP=$(od -A n -t u4 -j 512 -N 4 "$1" | awk '{print $1}')
      unset OFFSET
      if dd if="$1" bs=1 skip=$(( $SKIP + 2 )) count=5 2> /dev/null | grep -qe '^-lh[56d]-' ; then OFFSET=0; fi
      if dd if="$1" bs=1 skip=$(( $SKIP + 4 )) count=5 2> /dev/null | grep -qe '^-lh[56d]-' ; then OFFSET=2; fi
      if [ "$OFFSET" = "" ]; then
        echo "$1: unknown SFX."
      else
        dd if="$1" of="$ARCHIVE" skip=1 bs=$(( $SKIP + $OFFSET )) 2> /dev/null
      fi
    fi
  fi
  shift
done