Bash script that can uncompress: tar, gzip, rar

This code generally works exactly as it is supposed to. I'm learning bash I'm looking for some constructive help that could help me improve my work.

``
#!/bin/bash

usage()
{
echo "Program for uncompressing tar, gzip, rar archives"
echo "Allowed parametres: --help, --file, --input, --directory"
echo "Examples:"
echo "./uncompress.sh --file firstFile secondFile"
echo "./uncompress.sh --input inputFile.txt"
echo "./uncompress.sh --directory /home/"

}

uncompress_file()
{
if [ -f $1 ]
then
temp1=file $1 | cut -d: -f2 | grep tar

if [ "$temp1" != "" ]
then
echo "$1 is a tar archive, uncompressing..."
tar xf $1 > /dev/null
fi

temp1=file $1 | cut -d: -f2 | grep RAR

if [ "$temp1" != "" ]
then
echo "$1 is a rar archive, uncompressing..."
unrar e $1 > /dev/null
fi

temp1=file $1 | cut -d: -f2 | grep gzip`

if [ "$temp1" != "" ]
then
echo "$1 is a gzip archive, uncompressing..."
tar xzf $1 > /dev/null

fi

else
echo "$1 is not a valid file!"
fi
}

uncompress_dir()
{
for file in "$1"/*
do
if [ -f $file ]
then
uncompress_file $file
fi

if [ -d $file ]
then
uncompress_dir $file
fi

done

}

if [ "$1" = "--help" ]
then
usage
exit

fi

if test $# -lt 2
then echo "What about parametres?" 1>&2
exit 1
fi

param=$1;
shift;

if [ "$param" = "--file" ]
then

while [ $# -ne 0 ]
do
uncompress_file $1
shift
done
exit
fi

if [ "$param" = "--input" ]
then
if [ -f $1 ]
then
while read line
do
uncompress

StackExchange Code Review Q#25806, answer score: 4