# pack
compound, compress and encrypt files with tar, xz and scrypt

to create packages from files easily

# license
gpl3+

# usage examples
## create an automatically named package from multiple source files

    pack /tmp/1 /tmp/2
creates file "1.tar"

## create an explicity named package from multiple source files

    pack -t 3.tar /tmp/1 /tmp/2
creates file "3.tar"

## create an encrypted package

    pack -e 1 2
creates file "1.tar.e"

## create a compressed and encrypted package

    pack -ec 1 2
creates file "1.tar.xz.e"

## completely extract a package into the current working directory

    pack -u 1.tar.xz

## only decompress into the current working directory

    pack -uc 1.tar.xz
creates file "1.tar"

## completely extract a package into a target directory

    pack -ut /tmp 1.tar.xz

## compress a single file

    pack 1
creates 1.xz. tar is not used because it is only one file

## pack a list of paths read from standard input

    pack -p --
creates a tar archive with every file from a newline separated list read from standard-input

# general
* two modes: pack and unpack
* command-line interface and library
* uses stream processing and multiple processes
* when unpacking, multiple given source paths are unpacked in series

## format layers
* designated by filename suffixes
* layer-name and filename-suffix: encryption e compression xz compound tar
* there is a layer order that is adhered to (tar/xz/scrypt, for example the order xz/scrypt/tar is unsupported)

# command-line interface

$ pack --help
~~~
parameters
  options ... source-path ...
description
  one program for file and directory compounding, compression and encryption
options
  --about|-a
  --compression|-c
  --delete-input-files|-d
  --dry-run
  --encryption|-e
  --help|-h
  --implicit-compression|-i [number]  add compression if source is below a certain size. the optional value is in megabits.
  --interface
  --read-paths|-p string
  --target|-t string
  --unpack|-u
~~~

# dependencies
* [guile](https://www.gnu.org/software/guile/guile.html)
* [sph-lib](computer/software/sph-lib.html)
* optional
  * [tar](http://www.gnu.org/software/tar/tar.html)  (usually already installed)
  * [xz-utils](http://tukaani.org/xz/)
  * [scrypt file encryption utility](http://code.google.com/p/scrypt/)

# setup
* download from [releases](http://sph.mn/files/u/software/releases) or clone from git://git.sph.mn/sph-pack
* extract the downloaded archive
* link or copy the file exe/pack into a directory which is in the environment variable $PATH
* link or copy the files modules/* into a directory which is in the environment variable $GUILE_LOAD_PATH or any other guile load path

# behaviour in detail
* source: given source file paths or other source
* layers: layers requested (compression, compounding, encryption) for processing

## 1
* source: path ...
* layers: layer-already-indicated-in-path ...
* skip-indicated-layers

## 2
* unpack: true
* source: standard-input
* layers: compound
* not-supported

## 3
* unpack: true
* source: standard-input
* layers: compression
* target: false/directory
* standard-output

## 4
* unpack: true
* source: paths
* target: false
* target: current-working-directory

## 5
* unpack: true
* layers: false
* unpack-all-found-layers

## 6
* unpack: true
* source: paths-with-and-without-compression
* layer-compression: true
* remove-compression-from-paths-with-compression
* target: only-move-processed-files

## 7
* source: standard-input/paths
* target: "--"
* target: standard-output

## 8
* source: standard-input
* target: false
* target: standard-output

## 9
* source: paths
* target: false
* target: source-filename->target

## 10
* source: paths
* layer-compound: true

## 11
* source: directory-path
* layer-compound: true

## 12
* source: path
* layers: compound
* do-nothing

## 13
* layers: false
* layers: compression