diff --git a/shell/bash.sh b/shell/bash.sh
index 7b0f3c7..9e2b27e 100644
--- a/shell/bash.sh
+++ b/shell/bash.sh
@@ -1,13 +1,23 @@
-HISTCONTROL="ignorespace"
+[ "$(cat /proc/$$/comm)" = "bash" ] || return
 
-HISTSIZE=-1
+# completion
 
-HISTTIMEFORMAT="%Y%m%d %H%M%S "
 file="/usr/share/bash-completion/bash_completion"
 
 if [ -f "${file}" ]; then
 	. "${file}"
 fi
+
+# history
+
+HISTCONTROL="ignorespace"
+
+HISTSIZE=-1
+
+HISTTIMEFORMAT="%Y%m%d %H%M%S "
+
+# prompt
+
 ps1() {
 	local date host
 	local code="${1}"