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, 2016-2017 Free Software
   7 # Foundation, Inc.
   8
   9 # This file is part of GNU tar.
  10
  11 # GNU tar is free software; you can redistribute it and/or modify
  12 # it under the terms of the GNU General Public License as published by
  13 # the Free Software Foundation; either version 3 of the License, or
  14 # (at your option) any later version.
  15
  16 # GNU tar is distributed in the hope that it will be useful,
  17 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 # GNU General Public License for more details.
  20
  21 # You should have received a copy of the GNU General Public License
  22 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  23
  24 # dump_type FILE [N]
  25 # Print type character from block N (default 0) of tar archive FILE
  26 dump_type() {
  27   dd if="$1" skip=${2:-0} bs=512 count=1 2>/dev/null |
  28     tr '\0' ' ' |
  29     cut -c157
  30 }
  31
  32 case `dump_type "$1"` in
  33   [gx]) PAX=1;;
  34 esac
  35
  36 cat "$1"
  37 shift
  38 for f
  39 do
  40   SKIP=0
  41   T=`dump_type "$f"`
  42   if [ -n "$PAX" ]; then
  43     if [ "$T" = "g" ]; then
  44       # Global extended header.... 2 blocks
  45       # Extended header........... 2 blocks
  46       # Ustar header.............. 1 block
  47       # FIXME: This calculation is will fail for very long file names.
  48       SKIP=5
  49     fi
  50   else
  51     if [ "$T" = "V" ]; then
  52       T=`dump_type "$f" 1`
  53     fi
  54     if [ "$T" = "M" ]; then
  55       SKIP=$(($SKIP + 1))
  56     fi
  57   fi
  58   dd skip=$SKIP if="$f"
  59 done