Extracts through multiple layers of different types of compression.

extractor.sh

#!/bin/bash

# Extracts a file (through multiple layers) and prints it's contents
# Usage: $0 <filename>
# Options:
#  - [ENV] EXTRACT_DEBUG: Prints each step if variable is set

[[ $# -eq 0 ]] && { >&2 echo "Usage: $0 filename"; exit 1; }

# returns mimetype
# ignores tests for csv/json, etc files
function getmime {
    file -bi -e{compress,csv,json} "$1" | cut -d';' -f1
}

filename="$1"

# ext/tool map
declare -A extract

extract[application/x-tar]="tar xO"
extract[application/gzip]=gunzip
extract[application/x-xz]=unxz
extract[application/zip]=gunzip
extract[application/x-bzip2]=bunzip2

while :; do
    filemime="$( getmime "$filename" )"
    new_name="$( mktemp -p . )"

    [[ ! -z $EXTRACT_DEBUG ]] && { >&2 echo "Got mime $filemime; extracting $filename to $new_name"; }

    [[ "$filemime" =~ "text/*" ]] && { cat "$filename"; exit 0; }

    if [[ ! -z ${extract["$filemime"]} ]]; then
        ${extract["$filemime"]} < "$filename" > "$new_name"
        rm "$filename"
        filename="$new_name"
    else
        >&2 echo Unknown filetype "$filemime"
        exit 1
    fi
done