Dogcows Code - chaz/tar/blob - scripts/tarcat

   1 #! /bin/sh
   2 # Usage: tarcat volume1 volume2 ...
   3 # concatenates a GNU tar multi-volume archive into a single tar archive.
   4 # Author: Bruno Haible <bruno@clisp.org>, Sergey Poznyakoff <gray@gnu.org.ua>
   5
   6 # Copyright 2004-2005, 2010, 2013-2014 Free Software Foundation, Inc.
   7
   8 # This file is part of GNU tar.
   9
  10 # GNU tar is free software; you can redistribute it and/or modify
  11 # it under the terms of the GNU General Public License as published by
  12 # the Free Software Foundation; either version 3 of the License, or
  13 # (at your option) any later version.
  14
  15 # GNU tar is distributed in the hope that it will be useful,
  16 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 # GNU General Public License for more details.
  19
  20 # You should have received a copy of the GNU General Public License
  21 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  22
  23 # dump_type FILE [N]
  24 # Print type character from block N (default 0) of tar archive FILE
  25 dump_type() {
  26   dd if="$1" skip=${2:-0} bs=512 count=1 2>/dev/null |
  27     tr '\0' ' ' |
  28     cut -c157
  29 }
  30
  31 case `dump_type "$1"` in
  32   [gx]) PAX=1;;
  33 esac
  34
  35 cat "$1"
  36 shift
  37 for f
  38 do
  39   SKIP=0
  40   T=`dump_type "$f"`
  41   if [ -n "$PAX" ]; then
  42     if [ "$T" = "g" ]; then
  43       # Global extended header.... 2 blocks
  44       # Extended header........... 2 blocks
  45       # Ustar header.............. 1 block
  46       # FIXME: This calculation is will fail for very long file names.
  47       SKIP=5
  48     fi
  49   else
  50     if [ "$T" = "V" ]; then
  51       T=`dump_type "$f" 1`
  52     fi
  53     if [ "$T" = "M" ]; then
  54       SKIP=$(($SKIP + 1))
  55     fi
  56   fi
  57   dd skip=$SKIP if="$f"
  58 done