diff --git a/_setup.sh b/_setup.sh
index 7db9bb2..f7f0303 100755
--- a/_setup.sh
+++ b/_setup.sh
@@ -27,13 +27,13 @@ rm -r ~/.config/lf
 ln -s $PATH_PREFIX/config/lf ~/.config/lf
 
 # get tmux plugin manager going if needed
-if [[ ! -d ~/.tmux/plugins/tpm ]]; then
+if ! ( [ -d ~/.tmux -a -d ~/.tmux/plugins -a -d ~/.tmux/plugins/tpm ] ); then
     mkdir -p ~/.tmux/plugins/tpm
     git clone https://github.com/tmux-plugins/tpm ~/.tmux/plugins/tpm
 fi
 
 # get asdf going if needed
-if [[ ! -d ~/.asdf ]]; then
+if ! [ -d ~/.asdf ]; then
     git clone https://github.com/asdf-vm/asdf.git ~/.asdf
     cd ~/.asdf
     git checkout `git describe --tags --abbrev=0`