extract

#!/bin/bash
# extract FILE
#
while getopts "h" opt; do
    case $opt in
	h)
        echo "Supported extensions:"
        echo "* xz"
        echo "* tgz"
        echo "* tar"
        echo "* gz"
        echo "* tar.gz"
        echo "* zip"
        exit 0
	    ;;
	\?)
	    echo "Invalid option: -$OPTARG" >&2
	    ;;
    esac
done
if [[ "$#" -ne 1 ]]; then
    echo "Illegal number of parameters" >&2
    exit 1
fi

# Process file path
file=$1
if [[ "$file" =~ ^(.+)\.([^.]+)$ ]]; then
    filename="${BASH_REMATCH[1]}"
    file_ext="${BASH_REMATCH[2]}"
else
    filename="$file"
fi
case "$file_ext" in
    "xz" )
        if [[ "$filename" =~ ^(.+)\.([^.]+)$ ]]; then
            filename="${BASH_REMATCH[1]}"
            file_ext2="${BASH_REMATCH[2]}"
            if [[ "$file_ext2" = 'tar' ]]; then
                echo "Extracting TAR XZ file..."
                tar -xJf "$file"
                exit 0
            fi
        fi
        echo "Extracting XZ file..."
        xz -d "$file"
        ;;
    "tgz" )
        echo "Extracting TGZ file..."
        tar -xzvf "$file"
        exit 0
        ;;
    "gz" )
        if [[ "$filename" =~ ^(.+)\.([^.]+)$ ]]; then
            filename="${BASH_REMATCH[1]}"
            file_ext2="${BASH_REMATCH[2]}"
            if [[ "$file_ext2" = 'tar' ]]; then
                echo "Extracting TAR GZ file..."
                tar -xzvf "$file"
                exit 0
            fi
        fi
        echo "Extracting GZ file..."
        gunzip "$file"
        ;;
    "tar" )
        echo "Extracting TAR file..."
        tar -xf "$file"
        ;;
    "zip" )
        echo "Extracting ZIP file..."
        unzip "$file"
        ;;
    * )
        echo "No valid format specified by file extension or flag"
        exit 1
        ;;
esac