#! /bin/sh
# Usage: tarcat volume1 volume2 ...
# concatenates a GNU tar multi-volume archive into a single tar archive.
# Author: Bruno Haible <[email protected]>, Sergey Poznyakoff <[email protected]>

# dump_type FILE [N]
# Print type character from block N (default 0) of tar archive FILE
dump_type() {
dd if="$1" skip=${2:-0} bs=512 count=1 2>/dev/null |
tr '\0' ' ' |
cut -c157
}

case `dump_type "$1"` in
[gx]) PAX=1;;
esac

cat "$1"
shift
for f
do
SKIP=0
T=`dump_type "$f"`
if [ -n "$PAX" ]; then
if [ "$T" = "g" ]; then
# Global extended header.... 2 blocks
# Extended header........... 2 blocks
# Ustar header.............. 1 block
# FIXME: This calculation is will fail for very long file names.
SKIP=5
fi
else
if [ "$T" = "V" ]; then
T=`dump_type "$f" 1`
fi
if [ "$T" = "M" ]; then
SKIP=$(($SKIP + 1))
fi
fi
dd skip=$SKIP if="$f"
done