#!/bin/sh
# to view tar's

usage() {
 printf '%s\n' 'USAGE'\
 ' trq ARCHIVE (FILE)?'\
 ' trq - (FILE)?'\
 'WHERE'\
 ' ARCHIVE is the archive to inspect.'\
 ' -    reads from standard-input'\
 ' FILE is a file path.'
 exit 1
}

C=false
while [ $# -gt 0 ]; do
 case "$1" in
 *) break ;;
 esac; done
[ $# -lt 1 ] &&usage

F="$1" &&shift 1

if [ $# -gt 0 ]; then
 tar -xOf "$F" "$1"
else
 tar -tf "$F"
fi