diff --git a/install.sh b/install.sh
index 15824c4..c1da5b5 100755
--- a/install.sh
+++ b/install.sh
@@ -69,7 +69,7 @@ install_nvm_from_git() {
     mkdir -p "$NVM_DIR"
     command git clone "$(nvm_source git)" "$NVM_DIR"
   fi
-  cd "$NVM_DIR" && command git checkout --quiet $(nvm_latest_version)
+  cd "$NVM_DIR" && command git checkout --quiet "$(nvm_latest_version)"
   if [ ! -z "$(cd "$NVM_DIR" && git show-ref refs/heads/master)" ]; then
     if git branch --quiet 2>/dev/null; then
       cd "$NVM_DIR" && command git branch --quiet -D master >/dev/null 2>&1
@@ -123,15 +123,15 @@ nvm_detect_profile() {
   local DETECTED_PROFILE
   DETECTED_PROFILE=''
   local SHELLTYPE
-  SHELLTYPE="$(basename /$SHELL)"
+  SHELLTYPE="$(basename "/$SHELL")"
 
-  if [ $SHELLTYPE = "bash" ]; then
+  if [ "$SHELLTYPE" = "bash" ]; then
     if [ -f "$HOME/.bashrc" ]; then
       DETECTED_PROFILE="$HOME/.bashrc"
     elif [ -f "$HOME/.bash_profile" ]; then
       DETECTED_PROFILE="$HOME/.bash_profile"
     fi
-  elif [ $SHELLTYPE = "zsh" ]; then
+  elif [ "$SHELLTYPE" = "zsh" ]; then
     DETECTED_PROFILE="$HOME/.zshrc"
   fi