update zprofile

Author: Kazuaki NAKAMURA

.zprofile

@@ -3,7 +3,7 @@ for file in ~/.{exports,aliases,functions}; do
 done
 
 function powerline_precmd() {
-  PS1="$(~/.powerline-shell/powerline-shell.py $? --shell zsh 2> /dev/null)"
+    PS1="$(powerline-shell --shell zsh $?)"
 }
 
 function install_powerline_precmd() {
@@ -15,8 +15,8 @@ function install_powerline_precmd() {
   precmd_functions+=(powerline_precmd)
 }
 
-if [ "$TERM" != "linux" ]; then
-  install_powerline_precmd
+if [ "$TERM" != "linux" -a -x "$(command -v powerline-shell)" ]; then
+    install_powerline_precmd
 fi
 
 if [ -n "$LS_COLORS" ]; then