diff --git a/shell/shell.sh b/shell/shell.sh
index cb4557c..5676d0d 100644
--- a/shell/shell.sh
+++ b/shell/shell.sh
@@ -36,11 +36,19 @@ shell_configure() {
 	"bash")
 		# completion
 		local root="/usr/share/bash-completion"
-		local file path
-		for file in "bash_completion" "completions/git"; do
-			path="${root}/${file}"
-			[ -f "${path}" ] && . "${path}"
-		done
+		local file="bash_completion"
+		local path="${root}/${file}"
+		[ -f "${path}" ] && . "${path}"
+		root="${root}/completions"
+		if [ -d "${root}" ]; then
+			set \
+				"git" \
+				"tar"
+			for file in "${@}"; do
+				path="${root}/${file}"
+				[ -f "${path}" ] && . "${path}"
+			done
+		fi
 		# history
 		HISTCONTROL="ignorespace"
 		HISTSIZE=-1