erc: implement list_formats without patool

bin/erc-sh-archive

@@ -63,7 +63,12 @@ EOF
 list_formats()
 {
 	list_subformats
-	a='' patool formats | grep ".* files:" | sed "s/ .*//g"
+	if have_patool ; then
+		a='' patool formats | grep ".* files:" | sed "s/ .*//g"
+	else
+		echo "tar zip 7z tar.7z"
+		list_subformats
+	fi
 	# TODO: do not use patool formats in such case?
 	# See ArchiveCompressions in patool
 	list_extraformats

bin/tools_erc

@@ -78,6 +78,9 @@ extract_archive()
 
 	local type="$(get_archive_type "$arc")"
 	case "$type" in
+		tar.*)
+			docmd $HAVE_7Z x -so $arc | docmd $HAVE_7Z x -si -ttar
+			;;
 		*)
 			docmd $HAVE_7Z x $arc "$@"
 			#fatal "Not yet supported extracting of $type archives"