buildroot

#!/bin/sh

​

candidate="$1"

​

tar=`which $candidate`

if [ ! -x "$tar" ]; then

    tar=`which tar`

    if [ ! -x "$tar" ]; then

        # echo nothing: no suitable tar found

        exit 1

    fi

fi

​

# Output of 'tar --version' examples:

# tar (GNU tar) 1.15.1

# tar (GNU tar) 1.25

# bsdtar 2.8.3 - libarchive 2.8.3

version=`$tar --version | head -n 1 | sed 's/^.*\s\([0-9]\+\.\S\+\).*$/\1/'`

major=`echo "$version" | cut -d. -f1`

minor=`echo "$version" | cut -d. -f2`

bugfix=`echo "$version" | cut -d. -f3`

version_bsd=`$tar --version | grep 'bsdtar'`

if [ ! -z "${version_bsd}" ] ; then 

  # mark as invalid version - not all command line options are available

  major=0

  minor=0

fi

​

# Minimal version = 1.17 (previous versions do not correctly unpack archives

# containing hard-links if the --strip-components option is used).

major_min=1

minor_min=17

if [ $major -gt $major_min ]; then

    echo $tar

else

    if [ $major -eq $major_min -a $minor -ge $minor_min ]; then

        echo $tar

    else

        # echo nothing: no suitable tar found

        exit 1

    fi

fi