debextract

#!/bin/bash
#
# debextract - Wrapper to "dpkg-deb -x" for multiple files
#
#    Copyright (C) 2012 Rodrigo Silva (MestreLion) <linux@rodrigosilva.com>
#
#    This program is free software: you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation, either version 3 of the License, or
#    (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with this program. If not, see <http://www.gnu.org/licenses/gpl.html>
#
# Wrapper to extract multiple debian packages (*.deb). It automatically chooses
# a destination directory based on the deb's filename and also extracts the
# control information files (the DEBIAN directory inside the package)

usage() {
cat <<- USAGE
	Usage: $self [${main} options] [options] FILE...
USAGE
if [[ "$1" ]] ; then
	cat <<- USAGE
		Try '$self --help' for more information.
	USAGE
	exit 1
fi
cat <<-USAGE

	Extracts Debian Package files (.deb) to a directory matching their filenames

	Options:
	-h|--help     - show this page.
	-v|--verbose  - print more details about what is being done. Also enables
	                 verbosity for ${main}. Use -X/+X to enable or disable this
	-X|--vextract - turns ON  verbosity for ${main}. Useful if -v is not set
	+X            - turns OFF verbosity for ${main}. Useful if -v is set
	--destdir DIR - sets a directory for extraction of all packages. If ommited
	                 or blank, destination will be each package's current
	                 directory. In all cases, package filename will be appended
	                 to the final destination path.
	--nocontrol      - do not extract the control files. (DEBIAN directory)
	--controldir DIR - set the destination directory for the control files,
	                    relative to the extracted package directory. Ignored if
	                    --nocontrol is set. Default is DEBIAN.
	--onerror ACTION - What to do if an error occur when executing $main for a
	                    given file. Valid ACTION values are:
	          skip     - skip error and continue with next file, if any
	          quit     - quit immediately, do not extract any further files
	          ask      - if not last file, ask user what to do. Default action
	                   Regardless of the action chosen, in case of any error
	                   $self will always exit with ${main}'s last unsucessfull
	                   exit code
	${main} options:
	              - see ${main} --help or man ${main}

	FILE...       - package file(s) to extract, multiple files accepted

	The destination directory for extraction of each package will be the package
	filename without the .deb extension. Files other than *.deb will be
	silently ignored.

	Copyright (C) 2012 Rodrigo Silva (MestreLion) <linux@rodrigosilva.com>
	License: GPLv3 or later. See <http://www.gnu.org/licenses/gpl.html>
USAGE
exit 0
}

opterror() { echo "$self: $1" ; usage 1 ; }
missing()  { opterror "missing ${1:+$1 }operand" ; }

testaction() {
	[[ "$1" ]] || missing "action"
	actions=( skip quit ask )
	for action in "${actions[@]}"; do [[ "$action" == "$1" ]] && return ; done
	opterror "invalid action '$1'. valid options are: ${actions[*]}"
}

handleerror() {
	code=$1
	(( verbose )) && echo "$self: error $code in $main"
	(( $2 > 1 )) || return 0 # Noting to handle if this is the last file
	case "$action" in
	skip) return 0 ;;
	quit) return 1 ;;
	ask )
		local choice
		read -rp "(Q)uit, (S)kip, or Skip (A)ll ? " choice
		case "$choice" in
		[Aa]*) action="skip" ; return 0 ;;
		[Ss]*) return 0 ;;
		    *) return 1 ;; # Educating users not to blindly hit Enter :)
		esac
	esac
}

declare -a opts=()
self="${0##*/}"
main="dpkg-deb"
action="ask"
destdir=""
control=1
controldir="DEBIAN"
verbose=0
dverb=0
dquiet=0
code=0
ext="--extract"

# Loop options
while (( $# )); do
	case "$1" in
	-h|--help     ) usage                   ;;
	-v|--verbose  ) verbose=1               ;;
	-X|--vextract ) dverb=1                 ;;
	+X            ) dquiet=1                ;;
	-x|--extract  )                         ;; #I'm not so naive.Silently ignore
	--nocontrol   ) control=0               ;;
	--controldir=*) controldir="${1#*=}"    ;;
	--controldir  ) shift ; controldir="$1" ;;
	--destdir=*   ) destdir="${1#*=}"       ;;
	--destdir     ) shift ; destdir="$1"    ;;
	--onerror=*   ) testaction "${1#*=}"    ;;
	--onerror     ) shift ; testaction "$1" ;;
	--            ) shift ; break           ;;
	-*            ) opts+=( "$1" )          ;;
	*             ) break                   ;;
	esac
	shift
done

# Basic parser tests
[[ "$controldir" ]] || missing "control directory"

# Handle dpkg verbosity (done via extract command)
if ((verbose && !dquiet)) || (( !verbose && dverb )); then ext="--vextract"; fi

# Loop file arguments
(( $# )) || missing "file"
while (( $# )); do
	filename=${1##*/}
	filepath=${1%"$filename"}
	filetitle=${filename%.*}
	fileext=${filename#"$filetitle"}
	[[ "${fileext,,}" == ".deb" ]] || { shift ; continue ; }

	if [[ "$destdir" ]] ; then
		path="${destdir}/${filetitle}"
	else
		path="${filepath}${filetitle}"
	fi
	mkdir -p "$path" # make it easy for dpkg
	cmd1=("$main" "${opts[@]}" "$ext"    -- "$1" "${path//\/\///}"            )
	cmd2=("$main" "${opts[@]}" --control -- "$1" "${path//\/\///}/$controldir")
	if (( control )) ; then
		(( verbose )) && echo "$self: executing ${cmd1[@]} && ${cmd2[@]}"
		"${cmd1[@]}" && "${cmd2[@]}" || handleerror $? $# || break
	else
		(( verbose )) && echo "$self: executing ${cmd1[@]}"
		"${cmd1[@]}"                 || handleerror $? $# || break
	fi
	shift
done

(( verbose )) && (( code )) &&
	echo "$self: error(s) occurred, exiting with $main last error's code, $code"

exit $code