unfreeze file on linux

unfreeze

#!/bin/sh

usage ()
{
  echo "usage: unfreeze <some freezed file>"
  echo "supported file:"
  echo "  .tar.bz2"
  echo "  .tbz2"
  echo "  .tbz"
  echo "  .tgz"
  echo "  .zip"
  echo "  .tar"
  exit 1
}

if [ $# -ne 1 ]; then
  usage
fi

if [ `echo $1 | grep -E ".tar.bz2$"` ]; then
  echo "tar.bz2"
  tar -jxf $1
elif [ `echo $1 | grep -E ".tbz2$"` ]; then
  echo "tbz2"
  tar -jxf $1
elif [ `echo $1 | grep -E ".tbz$"` ]; then
  echo "tbz"
  tar zxvf $1
elif [ `echo $1 | grep -E ".tgz$"` ]; then
  echo "tgz"
  tar zxvf $1
elif [ `echo $1 | grep -E ".zip$"` ]; then
  echo "zip"
  unzip $1
elif [ `echo $1 | grep -E ".tar$"` ]; then
  echo "tar"
  tar xvf $1
else
  echo "unsupported file format: $1"
fi