diff --git a/bin/private/asdf-exec b/bin/private/asdf-exec
index 5181e842..2c46d6ba 100755
--- a/bin/private/asdf-exec
+++ b/bin/private/asdf-exec
@@ -20,7 +20,7 @@ IFS=' ' read -a versions <<< "$full_version"
 for version in "${versions[@]}"; do
   install_path=$(find_install_path $plugin_name $version)
 
-  if [ $version != "system" -a ! -d "$install_path" ]; then
+  if [ $version != "system" ] && [ ! -d "$install_path" ]; then
     echo "$plugin_name $version not installed"
     exit 1
   fi
diff --git a/lib/utils.sh b/lib/utils.sh
index ffe23586..4e5de7a0 100644
--- a/lib/utils.sh
+++ b/lib/utils.sh
@@ -59,7 +59,7 @@ check_if_plugin_exists() {
 check_if_version_exists() {
   local plugin_name=$1
   local version=$2
-  local version_dir=$(asdf_dir)/installs/$plugin/$version
+  local version_dir=$(asdf_dir)/installs/$plugin_name/$version
 
   # if version starts with path: use that directory
   if [ "${version/path:}" != "$version" ]; then
@@ -68,7 +68,7 @@ check_if_version_exists() {
 
   check_if_plugin_exists $plugin_name
 
-  if [ $version != "system" -a ! -d $version_dir ]; then
+  if [ $version != "system" ] && [ ! -d $version_dir ]; then
     display_error "version $version is not installed for $plugin_name"
     exit 1
   fi