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 # dump_type FILE [N]
   7 # Print type character from block N (default 0) of tar archive FILE
   8 dump_type() {
   9   dd if="$1" skip=${2:-0} bs=512 count=1 2>/dev/null |
  10     tr '\0' ' ' |
  11     cut -c157
  12 }
  13
  14 case `dump_type "$1"` in
  15   [gx]) PAX=1;;
  16 esac
  17
  18 cat "$1"
  19 shift
  20 for f
  21 do
  22   SKIP=0
  23   T=`dump_type "$f"`
  24   if [ -n "$PAX" ]; then
  25     if [ "$T" = "g" ]; then
  26       # Global extended header.... 2 blocks
  27       # Extended header........... 2 blocks
  28       # Ustar header.............. 1 block
  29       # FIXME: This calculation is will fail for very long file names.
  30       SKIP=5
  31     fi
  32   else
  33     if [ "$T" = "V" ]; then
  34       T=`dump_type "$f" 1`
  35     fi
  36     if [ "$T" = "M" ]; then
  37       SKIP=$(($SKIP + 1))
  38     fi
  39   fi
  40   dd skip=$SKIP if="$f"
  41 done
  42