1*4882a593Smuzhiyun#!/bin/sh 2*4882a593Smuzhiyun 3*4882a593Smuzhiyuncandidate="$1" 4*4882a593Smuzhiyun 5*4882a593Smuzhiyuntar=`which $candidate` 6*4882a593Smuzhiyunif [ ! -x "$tar" ]; then 7*4882a593Smuzhiyun tar=`which tar` 8*4882a593Smuzhiyun if [ ! -x "$tar" ]; then 9*4882a593Smuzhiyun # echo nothing: no suitable tar found 10*4882a593Smuzhiyun exit 1 11*4882a593Smuzhiyun fi 12*4882a593Smuzhiyunfi 13*4882a593Smuzhiyun 14*4882a593Smuzhiyun# Output of 'tar --version' examples: 15*4882a593Smuzhiyun# tar (GNU tar) 1.15.1 16*4882a593Smuzhiyun# tar (GNU tar) 1.25 17*4882a593Smuzhiyun# bsdtar 2.8.3 - libarchive 2.8.3 18*4882a593Smuzhiyunversion=`$tar --version | head -n 1 | sed 's/^.*\s\([0-9]\+\.\S\+\).*$/\1/'` 19*4882a593Smuzhiyunmajor=`echo "$version" | cut -d. -f1` 20*4882a593Smuzhiyunminor=`echo "$version" | cut -d. -f2` 21*4882a593Smuzhiyunbugfix=`echo "$version" | cut -d. -f3` 22*4882a593Smuzhiyunversion_bsd=`$tar --version | grep 'bsdtar'` 23*4882a593Smuzhiyun 24*4882a593Smuzhiyun# BSD tar does not have all the command-line options 25*4882a593Smuzhiyunif [ -n "${version_bsd}" ] ; then 26*4882a593Smuzhiyun # echo nothing: no suitable tar found 27*4882a593Smuzhiyun exit 1 28*4882a593Smuzhiyunfi 29*4882a593Smuzhiyun 30*4882a593Smuzhiyun# Minimal version = 1.27 (previous versions do not correctly unpack archives 31*4882a593Smuzhiyun# containing hard-links if the --strip-components option is used or create 32*4882a593Smuzhiyun# different gnu long link headers for path elements > 100 characters). 33*4882a593Smuzhiyunmajor_min=1 34*4882a593Smuzhiyunminor_min=27 35*4882a593Smuzhiyun 36*4882a593Smuzhiyunif [ $major -lt $major_min ]; then 37*4882a593Smuzhiyun # echo nothing: no suitable tar found 38*4882a593Smuzhiyun exit 1 39*4882a593Smuzhiyunfi 40*4882a593Smuzhiyun 41*4882a593Smuzhiyunif [ $major -eq $major_min -a $minor -lt $minor_min ]; then 42*4882a593Smuzhiyun # echo nothing: no suitable tar found 43*4882a593Smuzhiyun exit 1 44*4882a593Smuzhiyunfi 45*4882a593Smuzhiyun 46*4882a593Smuzhiyun# valid 47*4882a593Smuzhiyunecho $tar 48