diff --git a/test/current_command.bats b/test/current_command.bats
index 65a230d6..b32db875 100755
--- a/test/current_command.bats
+++ b/test/current_command.bats
@@ -18,8 +18,8 @@ teardown() {
 }
 
 @test "current should derive from the current .tool-versions" {
-  cd $PROJECT_DIR
-  echo 'dummy 1.1.0' >>$PROJECT_DIR/.tool-versions
+  cd "$PROJECT_DIR"
+  echo 'dummy 1.1.0' >>"$PROJECT_DIR/.tool-versions"
   expected="dummy           1.1.0           $PROJECT_DIR/.tool-versions"
 
   run asdf current "dummy"
@@ -28,8 +28,8 @@ teardown() {
 }
 
 @test "current should handle long version name" {
-  cd $PROJECT_DIR
-  echo "dummy nightly-2000-01-01" >>$PROJECT_DIR/.tool-versions
+  cd "$PROJECT_DIR"
+  echo "dummy nightly-2000-01-01" >>"$PROJECT_DIR/.tool-versions"
   expected="dummy           nightly-2000-01-01 $PROJECT_DIR/.tool-versions"
 
   run asdf current "dummy"
@@ -38,8 +38,8 @@ teardown() {
 }
 
 @test "current should handle multiple versions" {
-  cd $PROJECT_DIR
-  echo "dummy 1.2.0 1.1.0" >>$PROJECT_DIR/.tool-versions
+  cd "$PROJECT_DIR"
+  echo "dummy 1.2.0 1.1.0" >>"$PROJECT_DIR/.tool-versions"
   expected="dummy           1.2.0 1.1.0     $PROJECT_DIR/.tool-versions"
 
   run asdf current "dummy"
@@ -68,7 +68,7 @@ teardown() {
 }
 
 @test "current should error when no version is set" {
-  cd $PROJECT_DIR
+  cd "$PROJECT_DIR"
   expected="dummy           ______          No version is set. Run \"asdf <global|shell|local> dummy <version>\""
 
   run asdf current "dummy"
@@ -77,8 +77,8 @@ teardown() {
 }
 
 @test "current should error when a version is set that isn't installed" {
-  cd $PROJECT_DIR
-  echo 'dummy 9.9.9' >>$PROJECT_DIR/.tool-versions
+  cd "$PROJECT_DIR"
+  echo 'dummy 9.9.9' >>"$PROJECT_DIR/.tool-versions"
   expected="dummy           9.9.9           Not installed. Run \"asdf install dummy 9.9.9\""
 
   run asdf current "dummy"
@@ -96,9 +96,9 @@ teardown() {
 
   install_mock_plugin "baz"
 
-  cd $PROJECT_DIR
-  echo 'dummy 1.1.0' >>$PROJECT_DIR/.tool-versions
-  echo 'foobar 1.0.0' >>$PROJECT_DIR/.tool-versions
+  cd "$PROJECT_DIR"
+  echo 'dummy 1.1.0' >>"$PROJECT_DIR/.tool-versions"
+  echo 'foobar 1.0.0' >>"$PROJECT_DIR/.tool-versions"
 
   run asdf current
   expected="baz             ______          No version is set. Run \"asdf <global|shell|local> baz <version>\"
@@ -115,9 +115,9 @@ foobar          1.0.0           $PROJECT_DIR/.tool-versions"
   install_mock_plugin "y"
   install_mock_plugin_version "y" "2.1.0"
 
-  cd $PROJECT_DIR
-  echo 'dummy 1.1.0' >>$PROJECT_DIR/.tool-versions
-  echo 'y 2.1.0' >>$PROJECT_DIR/.tool-versions
+  cd "$PROJECT_DIR"
+  echo 'dummy 1.1.0' >>"$PROJECT_DIR/.tool-versions"
+  echo 'y 2.1.0' >>"$PROJECT_DIR/.tool-versions"
 
   run asdf current "y"
   [ "$status" -eq 0 ]
diff --git a/test/get_asdf_config_value.bats b/test/get_asdf_config_value.bats
index bcdc0873..b57043b1 100644
--- a/test/get_asdf_config_value.bats
+++ b/test/get_asdf_config_value.bats
@@ -19,8 +19,8 @@ EOM
 }
 
 teardown() {
-  rm $ASDF_CONFIG_FILE
-  rm $ASDF_CONFIG_DEFAULT_FILE
+  rm "$ASDF_CONFIG_FILE"
+  rm "$ASDF_CONFIG_DEFAULT_FILE"
   unset ASDF_CONFIG_DEFAULT_FILE
   unset ASDF_CONFIG_FILE
 }
@@ -40,7 +40,7 @@ teardown() {
 }
 
 @test "get_config returns config file complete value including '=' symbols" {
-  cat >>$ASDF_CONFIG_FILE <<-'EOM'
+  cat >>"$ASDF_CONFIG_FILE" <<-'EOM'
 key3 = VAR=val
 EOM
 
diff --git a/test/help_command.bats b/test/help_command.bats
index 12a0a552..51af8ee4 100644
--- a/test/help_command.bats
+++ b/test/help_command.bats
@@ -18,7 +18,7 @@ teardown() {
 }
 
 @test "help should show dummy plugin help" {
-  cd $PROJECT_DIR
+  cd "$PROJECT_DIR"
 
   run asdf help "dummy"
 
@@ -34,7 +34,7 @@ EOF
 }
 
 @test "help should show dummy plugin help specific to version when version is present" {
-  cd $PROJECT_DIR
+  cd "$PROJECT_DIR"
 
   run asdf help "dummy" "1.2.3"
 
@@ -48,12 +48,12 @@ Details specific for version 1.2.3
 EOF
   )"
   [ "$status" -eq 0 ]
-  echo $output
+  echo "$output"
   [ "$output" = "$expected_output" ]
 }
 
 @test "help should fail for unknown plugins" {
-  cd $PROJECT_DIR
+  cd "$PROJECT_DIR"
 
   run asdf help "sunny"
   [ "$status" -eq 1 ]
@@ -61,7 +61,7 @@ EOF
 }
 
 @test "help should fail when plugin doesn't have documentation callback" {
-  cd $PROJECT_DIR
+  cd "$PROJECT_DIR"
 
   run asdf help "legacy-dummy"
   [ "$status" -eq 1 ]
@@ -69,7 +69,7 @@ EOF
 }
 
 @test "help should show asdf help when no plugin name is provided" {
-  cd $PROJECT_DIR
+  cd "$PROJECT_DIR"
 
   run asdf help
 
diff --git a/test/info_command.bats b/test/info_command.bats
index ddd9fcd4..57e69dec 100644
--- a/test/info_command.bats
+++ b/test/info_command.bats
@@ -18,7 +18,7 @@ teardown() {
 }
 
 @test "info should show os, shell and asdf debug information" {
-  cd $PROJECT_DIR
+  cd "$PROJECT_DIR"
 
   run asdf info
 
diff --git a/test/install_command.bats b/test/install_command.bats
index 1f43bb68..f5928ec0 100644
--- a/test/install_command.bats
+++ b/test/install_command.bats
@@ -29,7 +29,7 @@ teardown() {
 }
 
 @test "install_command without arguments installs even if the user is terrible and does not use newlines" {
-  cd $PROJECT_DIR
+  cd "$PROJECT_DIR"
   echo -n 'dummy 1.2.0' >".tool-versions"
   run asdf install
   [ "$status" -eq 0 ]
@@ -37,7 +37,7 @@ teardown() {
 }
 
 @test "install_command with only name installs the version in .tool-versions" {
-  cd $PROJECT_DIR
+  cd "$PROJECT_DIR"
   echo -n 'dummy 1.2.0' >".tool-versions"
   run asdf install dummy
   [ "$status" -eq 0 ]
@@ -84,15 +84,15 @@ teardown() {
   run asdf install dummy 1.1.0
   [ "$status" -eq 0 ]
 
-  run grep "asdf-plugin: dummy 1.1.0" $ASDF_DIR/shims/dummy
+  run grep "asdf-plugin: dummy 1.1.0" "$ASDF_DIR/shims/dummy"
   [ "$status" -eq 0 ]
 
-  run grep "asdf-plugin: dummy 1.0.0" $ASDF_DIR/shims/dummy
+  run grep "asdf-plugin: dummy 1.0.0" "$ASDF_DIR/shims/dummy"
   [ "$status" -eq 1 ]
 
   run asdf install dummy 1.0.0
   [ "$status" -eq 0 ]
-  run grep "asdf-plugin: dummy 1.0.0" $ASDF_DIR/shims/dummy
+  run grep "asdf-plugin: dummy 1.0.0" "$ASDF_DIR/shims/dummy"
   [ "$status" -eq 0 ]
 
   run grep "# asdf-plugin: dummy 1.0.0"$'\n'"# asdf-plugin: dummy 1.1.0" "$ASDF_DIR/shims/dummy"
@@ -103,8 +103,8 @@ teardown() {
 }
 
 @test "install_command without arguments should not generate shim for subdir" {
-  cd $PROJECT_DIR
-  echo 'dummy 1.0.0' >$PROJECT_DIR/.tool-versions
+  cd "$PROJECT_DIR"
+  echo 'dummy 1.0.0' >"$PROJECT_DIR/.tool-versions"
 
   run asdf install
   [ "$status" -eq 0 ]
@@ -114,14 +114,14 @@ teardown() {
 
 @test "install_command without arguments should generate shim that passes all arguments to executable" {
   # asdf lib needed to run generated shims
-  cp -rf $BATS_TEST_DIRNAME/../{bin,lib} $ASDF_DIR/
+  cp -rf "$BATS_TEST_DIRNAME"/../{bin,lib} "$ASDF_DIR/"
 
-  cd $PROJECT_DIR
-  echo 'dummy 1.0.0' >$PROJECT_DIR/.tool-versions
+  cd "$PROJECT_DIR"
+  echo 'dummy 1.0.0' >"$PROJECT_DIR/.tool-versions"
   run asdf install
 
   # execute the generated shim
-  run $ASDF_DIR/shims/dummy world hello
+  run "$ASDF_DIR/shims/dummy" world hello
   [ "$status" -eq 0 ]
   [ "$output" = "This is Dummy 1.0.0! hello world" ]
 }
@@ -134,8 +134,8 @@ teardown() {
 }
 
 @test "install_command fails if the plugin is not installed" {
-  cd $PROJECT_DIR
-  echo 'other_dummy 1.0.0' >$PROJECT_DIR/.tool-versions
+  cd "$PROJECT_DIR"
+  echo 'other_dummy 1.0.0' >"$PROJECT_DIR/.tool-versions"
 
   run asdf install
   [ "$status" -eq 1 ]
@@ -143,8 +143,8 @@ teardown() {
 }
 
 @test "install_command fails if the plugin is not installed without collisions" {
-  cd $PROJECT_DIR
-  printf "dummy 1.0.0\ndum 1.0.0" >$PROJECT_DIR/.tool-versions
+  cd "$PROJECT_DIR"
+  printf "dummy 1.0.0\ndum 1.0.0" >"$PROJECT_DIR/.tool-versions"
 
   run asdf install
   [ "$status" -eq 1 ]
@@ -152,7 +152,7 @@ teardown() {
 }
 
 @test "install_command fails when tool is specified but no version of the tool is configured in config file" {
-  echo 'dummy 1.0.0' >$PROJECT_DIR/.tool-versions
+  echo 'dummy 1.0.0' >"$PROJECT_DIR/.tool-versions"
   run asdf install other-dummy
   [ "$status" -eq 1 ]
   [ "$output" = "No versions specified for other-dummy in config files or environment" ]
@@ -160,7 +160,7 @@ teardown() {
 }
 
 @test "install_command fails when two tools are specified with no versions" {
-  printf 'dummy 1.0.0\nother-dummy 2.0.0' >$PROJECT_DIR/.tool-versions
+  printf 'dummy 1.0.0\nother-dummy 2.0.0' >"$PROJECT_DIR/.tool-versions"
   run asdf install dummy other-dummy
   [ "$status" -eq 1 ]
   [ "$output" = "Dummy couldn't install version: other-dummy (on purpose)" ]
@@ -170,12 +170,12 @@ teardown() {
 
 @test "install_command without arguments uses a parent directory .tool-versions file if present" {
   # asdf lib needed to run generated shims
-  cp -rf $BATS_TEST_DIRNAME/../{bin,lib} $ASDF_DIR/
+  cp -rf "$BATS_TEST_DIRNAME"/../{bin,lib} "$ASDF_DIR/"
 
-  echo 'dummy 1.0.0' >$PROJECT_DIR/.tool-versions
-  mkdir -p $PROJECT_DIR/child
+  echo 'dummy 1.0.0' >"$PROJECT_DIR/.tool-versions"
+  mkdir -p "$PROJECT_DIR/child"
 
-  cd $PROJECT_DIR/child
+  cd "$PROJECT_DIR/child"
 
   run asdf install
 
@@ -185,11 +185,11 @@ teardown() {
 }
 
 @test "install_command installs multiple tool versions when they are specified in a .tool-versions file" {
-  echo 'dummy 1.0.0 1.2.0' >$PROJECT_DIR/.tool-versions
-  cd $PROJECT_DIR
+  echo 'dummy 1.0.0 1.2.0' >"$PROJECT_DIR/.tool-versions"
+  cd "$PROJECT_DIR"
 
   run asdf install
-  echo $output
+  echo "$output"
   [ "$status" -eq 0 ]
 
   [ "$(cat "$ASDF_DIR/installs/dummy/1.0.0/version")" = "1.0.0" ]
@@ -203,7 +203,7 @@ teardown() {
 }
 
 @test "install command executes configured pre plugin install hook" {
-  cat >$HOME/.asdfrc <<-'EOM'
+  cat >"$HOME/.asdfrc" <<-'EOM'
 pre_asdf_install_dummy = echo will install dummy $1
 EOM
 
@@ -212,7 +212,7 @@ EOM
 }
 
 @test "install command executes configured post plugin install hook" {
-  cat >$HOME/.asdfrc <<-'EOM'
+  cat >"$HOME/.asdfrc" <<-'EOM'
 post_asdf_install_dummy = echo HEY $version FROM $plugin_name
 EOM
 
@@ -234,8 +234,8 @@ EOM
   echo 'legacy_version_file = yes' >"$HOME/.asdfrc"
   echo '1.2.0' >>"$PROJECT_DIR/.dummy-version"
 
-  mkdir -p $PROJECT_DIR/child
-  cd $PROJECT_DIR/child
+  mkdir -p "$PROJECT_DIR/child"
+  cd "$PROJECT_DIR/child"
 
   run asdf install
   [ "$status" -eq 0 ]
@@ -272,7 +272,7 @@ EOM
 @test "install_command keeps the download directory when always_keep_download setting is true" {
   echo 'always_keep_download = yes' >"$HOME/.asdfrc"
   run asdf install dummy 1.1.0
-  echo $output
+  echo "$output"
   [ "$status" -eq 0 ]
   [ -d "$ASDF_DIR/downloads/dummy/1.1.0" ]
   [ "$(cat "$ASDF_DIR/installs/dummy/1.1.0/version")" = "1.1.0" ]
@@ -280,7 +280,7 @@ EOM
 
 @test "install_command fails when download script exits with non-zero code" {
   run asdf install dummy-broken 1.0.0
-  echo $output
+  echo "$output"
   [ "$status" -eq 1 ]
   [ ! -d "$ASDF_DIR/downloads/dummy-broken/1.1.0" ]
   [ ! -d "$ASDF_DIR/installs/dummy-broken/1.1.0" ]
diff --git a/test/list_command.bats b/test/list_command.bats
index 7bc3ddf8..7d14626b 100644
--- a/test/list_command.bats
+++ b/test/list_command.bats
@@ -25,8 +25,8 @@ teardown() {
 }
 
 @test "list_command should list plugins with installed versions and any selected versions marked with asterisk" {
-  cd $PROJECT_DIR
-  echo 'dummy 1.1.0' >>$PROJECT_DIR/.tool-versions
+  cd "$PROJECT_DIR"
+  echo 'dummy 1.1.0' >>"$PROJECT_DIR/.tool-versions"
   run asdf install dummy 1.0.0
   run asdf install dummy 1.1.0
 
@@ -95,14 +95,14 @@ teardown() {
 
 @test "list_all_command fails when list-all script exits with non-zero code" {
   run asdf list-all dummy-broken
-  echo $output
+  echo "$output"
   [ "$status" -eq 1 ]
   [[ "$output" == "Plugin dummy-broken's list-all callback script failed with output:"* ]]
 }
 
 @test "list_all_command displays stderr then stdout when failing" {
   run asdf list-all dummy-broken
-  echo $output
+  echo "$output"
   [[ "$output" == *"List-all failed!"* ]]
   [[ "$output" == *"Attempting to list versions" ]]
 }
diff --git a/test/plugin_add_command.bats b/test/plugin_add_command.bats
index dc22e62f..78bf845c 100644
--- a/test/plugin_add_command.bats
+++ b/test/plugin_add_command.bats
@@ -121,7 +121,7 @@ teardown() {
 @test "plugin_add command executes configured pre hook (generic)" {
   install_mock_plugin_repo "dummy"
 
-  cat >$HOME/.asdfrc <<-'EOM'
+  cat >"$HOME/.asdfrc" <<-'EOM'
 pre_asdf_plugin_add = echo ADD ${@}
 EOM
 
@@ -135,7 +135,7 @@ plugin add path=${ASDF_DIR}/plugins/dummy source_url=${BASE_DIR}/repo-dummy"
 @test "plugin_add command executes configured pre hook (specific)" {
   install_mock_plugin_repo "dummy"
 
-  cat >$HOME/.asdfrc <<-'EOM'
+  cat >"$HOME/.asdfrc" <<-'EOM'
 pre_asdf_plugin_add_dummy = echo ADD
 EOM
 
@@ -149,7 +149,7 @@ plugin add path=${ASDF_DIR}/plugins/dummy source_url=${BASE_DIR}/repo-dummy"
 @test "plugin_add command executes configured post hook (generic)" {
   install_mock_plugin_repo "dummy"
 
-  cat >$HOME/.asdfrc <<-'EOM'
+  cat >"$HOME/.asdfrc" <<-'EOM'
 post_asdf_plugin_add = echo ADD ${@}
 EOM
 
@@ -163,7 +163,7 @@ ADD dummy"
 @test "plugin_add command executes configured post hook (specific)" {
   install_mock_plugin_repo "dummy"
 
-  cat >$HOME/.asdfrc <<-'EOM'
+  cat >"$HOME/.asdfrc" <<-'EOM'
 post_asdf_plugin_add_dummy = echo ADD
 EOM
 
diff --git a/test/plugin_extension_command.bats b/test/plugin_extension_command.bats
index fa5883aa..b83a1ab5 100644
--- a/test/plugin_extension_command.bats
+++ b/test/plugin_extension_command.bats
@@ -29,7 +29,7 @@ teardown() {
 }
 
 @test "asdf help shows extension commands for plugin with hyphens in the name" {
-  cd $PROJECT_DIR
+  cd "$PROJECT_DIR"
 
   plugin_name=dummy-hyphenated
   install_mock_plugin $plugin_name
diff --git a/test/plugin_update_command.bats b/test/plugin_update_command.bats
index c31b4ec0..e8ce1b0f 100644
--- a/test/plugin_update_command.bats
+++ b/test/plugin_update_command.bats
@@ -157,7 +157,7 @@ teardown() {
 }
 
 @test "asdf plugin-update executes configured pre hook (generic)" {
-  cat >$HOME/.asdfrc <<-'EOM'
+  cat >"$HOME/.asdfrc" <<-'EOM'
 pre_asdf_plugin_update = echo UPDATE ${@}
 EOM
 
@@ -173,7 +173,7 @@ EOM
 }
 
 @test "asdf plugin-update executes configured pre hook (specific)" {
-  cat >$HOME/.asdfrc <<-'EOM'
+  cat >"$HOME/.asdfrc" <<-'EOM'
 pre_asdf_plugin_update_dummy = echo UPDATE
 EOM
 
@@ -189,7 +189,7 @@ EOM
 }
 
 @test "asdf plugin-update executes configured post hook (generic)" {
-  cat >$HOME/.asdfrc <<-'EOM'
+  cat >"$HOME/.asdfrc" <<-'EOM'
 post_asdf_plugin_update = echo UPDATE ${@}
 EOM
 
@@ -206,7 +206,7 @@ UPDATE dummy"
 }
 
 @test "asdf plugin-update executes configured post hook (specific)" {
-  cat >$HOME/.asdfrc <<-'EOM'
+  cat >"$HOME/.asdfrc" <<-'EOM'
 post_asdf_plugin_update_dummy = echo UPDATE
 EOM
 
diff --git a/test/remove_command.bats b/test/remove_command.bats
index d2351fe9..be17aeeb 100644
--- a/test/remove_command.bats
+++ b/test/remove_command.bats
@@ -77,7 +77,7 @@ teardown() {
 @test "plugin_remove_command executes configured pre hook (generic)" {
   install_dummy_plugin
 
-  cat >$HOME/.asdfrc <<-'EOM'
+  cat >"$HOME/.asdfrc" <<-'EOM'
 pre_asdf_plugin_remove = echo REMOVE ${@}
 EOM
 
@@ -91,7 +91,7 @@ plugin-remove ${ASDF_DIR}/plugins/dummy"
 @test "plugin_remove_command executes configured pre hook (specific)" {
   install_dummy_plugin
 
-  cat >$HOME/.asdfrc <<-'EOM'
+  cat >"$HOME/.asdfrc" <<-'EOM'
 pre_asdf_plugin_remove_dummy = echo REMOVE
 EOM
 
@@ -105,7 +105,7 @@ plugin-remove ${ASDF_DIR}/plugins/dummy"
 @test "plugin_remove_command executes configured post hook (generic)" {
   install_dummy_plugin
 
-  cat >$HOME/.asdfrc <<-'EOM'
+  cat >"$HOME/.asdfrc" <<-'EOM'
 post_asdf_plugin_remove = echo REMOVE ${@}
 EOM
 
@@ -119,7 +119,7 @@ REMOVE dummy"
 @test "plugin_remove_command executes configured post hook (specific)" {
   install_dummy_plugin
 
-  cat >$HOME/.asdfrc <<-'EOM'
+  cat >"$HOME/.asdfrc" <<-'EOM'
 post_asdf_plugin_remove_dummy = echo REMOVE
 EOM
 
diff --git a/test/shim_env_command.bats b/test/shim_env_command.bats
index 84820e6d..8e316da6 100644
--- a/test/shim_env_command.bats
+++ b/test/shim_env_command.bats
@@ -11,7 +11,7 @@ setup() {
   cd "$PROJECT_DIR"
 
   # asdf lib needed to run generated shims
-  cp -rf $BATS_TEST_DIRNAME/../{bin,lib} $ASDF_DIR/
+  cp -rf "$BATS_TEST_DIRNAME"/../{bin,lib} "$ASDF_DIR/"
 }
 
 teardown() {
@@ -25,7 +25,7 @@ teardown() {
 }
 
 @test "asdf env should execute under the environment used for a shim" {
-  echo "dummy 1.0" >$PROJECT_DIR/.tool-versions
+  echo "dummy 1.0" >"$PROJECT_DIR/.tool-versions"
   run asdf install
 
   run asdf env dummy which dummy
@@ -34,7 +34,7 @@ teardown() {
 }
 
 @test "asdf env should execute under plugin custom environment used for a shim" {
-  echo "dummy 1.0" >$PROJECT_DIR/.tool-versions
+  echo "dummy 1.0" >"$PROJECT_DIR/.tool-versions"
   run asdf install
 
   echo "export FOO=bar" >"$ASDF_DIR/plugins/dummy/bin/exec-env"
@@ -46,13 +46,13 @@ teardown() {
 }
 
 @test "asdf env should ignore plugin custom environment on system version" {
-  echo "dummy 1.0" >$PROJECT_DIR/.tool-versions
+  echo "dummy 1.0" >"$PROJECT_DIR/.tool-versions"
   run asdf install
 
   echo "export FOO=bar" >"$ASDF_DIR/plugins/dummy/bin/exec-env"
   chmod +x "$ASDF_DIR/plugins/dummy/bin/exec-env"
 
-  echo "dummy system" >$PROJECT_DIR/.tool-versions
+  echo "dummy system" >"$PROJECT_DIR/.tool-versions"
 
   run asdf env dummy
   [ "$status" -eq 0 ]
@@ -67,7 +67,7 @@ teardown() {
 }
 
 @test "asdf env should set PATH correctly" {
-  echo "dummy 1.0" >$PROJECT_DIR/.tool-versions
+  echo "dummy 1.0" >"$PROJECT_DIR/.tool-versions"
   run asdf install
 
   run asdf env dummy
diff --git a/test/shim_exec.bats b/test/shim_exec.bats
index a38c0c9b..01709e51 100644
--- a/test/shim_exec.bats
+++ b/test/shim_exec.bats
@@ -11,7 +11,7 @@ setup() {
   cd "$PROJECT_DIR"
 
   # asdf lib needed to run generated shims
-  cp -rf $BATS_TEST_DIRNAME/../{bin,lib} $ASDF_DIR/
+  cp -rf "$BATS_TEST_DIRNAME"/../{bin,lib} "$ASDF_DIR/"
 }
 
 teardown() {
@@ -25,7 +25,7 @@ teardown() {
 }
 
 @test "asdf exec should pass all arguments to executable" {
-  echo "dummy 1.0" >$PROJECT_DIR/.tool-versions
+  echo "dummy 1.0" >"$PROJECT_DIR/.tool-versions"
   run asdf install
 
   run asdf exec dummy world hello
@@ -34,7 +34,7 @@ teardown() {
 }
 
 @test "asdf exec should pass all arguments to executable even if shim is not in PATH" {
-  echo "dummy 1.0" >$PROJECT_DIR/.tool-versions
+  echo "dummy 1.0" >"$PROJECT_DIR/.tool-versions"
   run asdf install
 
   path=$(echo "$PATH" | sed -e "s|$(asdf_data_dir)/shims||g; s|::|:|g")
@@ -48,16 +48,16 @@ teardown() {
 }
 
 @test "shim exec should pass all arguments to executable" {
-  echo "dummy 1.0" >$PROJECT_DIR/.tool-versions
+  echo "dummy 1.0" >"$PROJECT_DIR/.tool-versions"
   run asdf install
 
-  run $ASDF_DIR/shims/dummy world hello
+  run "$ASDF_DIR/shims/dummy" world hello
   [ "$output" = "This is Dummy 1.0! hello world" ]
   [ "$status" -eq 0 ]
 }
 
 @test "shim exec should pass stdin to executable" {
-  echo "dummy 1.0" >$PROJECT_DIR/.tool-versions
+  echo "dummy 1.0" >"$PROJECT_DIR/.tool-versions"
   run asdf install
 
   echo "tr [:lower:] [:upper:]" >"$ASDF_DIR/installs/dummy/1.0/bin/upper"
@@ -73,9 +73,9 @@ teardown() {
 @test "shim exec should fail if no version is selected" {
   run asdf install dummy 1.0
 
-  touch $PROJECT_DIR/.tool-versions
+  touch "$PROJECT_DIR/.tool-versions"
 
-  run $ASDF_DIR/shims/dummy world hello
+  run "$ASDF_DIR/shims/dummy" world hello
   [ "$status" -eq 126 ]
   echo "$output" | grep -q "No version is set for command dummy" 2>/dev/null
 }
@@ -84,9 +84,9 @@ teardown() {
   run asdf install dummy 1.0
   run asdf install dummy 2.0.0
 
-  touch $PROJECT_DIR/.tool-versions
+  touch "$PROJECT_DIR/.tool-versions"
 
-  run $ASDF_DIR/shims/dummy world hello
+  run "$ASDF_DIR/shims/dummy" world hello
   [ "$status" -eq 126 ]
 
   echo "$output" | grep -q "No version is set for command dummy" 2>/dev/null
@@ -97,14 +97,14 @@ teardown() {
 
 @test "shim exec should suggest different plugins providing same tool when no version is selected" {
   # Another fake plugin with 'dummy' executable
-  cp -rf $ASDF_DIR/plugins/dummy $ASDF_DIR/plugins/mummy
+  cp -rf "$ASDF_DIR/plugins/dummy" "$ASDF_DIR/plugins/mummy"
 
   run asdf install dummy 1.0
   run asdf install mummy 3.0
 
-  touch $PROJECT_DIR/.tool-versions
+  touch "$PROJECT_DIR/.tool-versions"
 
-  run $ASDF_DIR/shims/dummy world hello
+  run "$ASDF_DIR/shims/dummy" world hello
   [ "$status" -eq 126 ]
 
   echo "$output" | grep -q "No version is set for command dummy" 2>/dev/null
@@ -116,9 +116,9 @@ teardown() {
 @test "shim exec should suggest to install missing version" {
   run asdf install dummy 1.0
 
-  echo "dummy 2.0.0 1.3" >$PROJECT_DIR/.tool-versions
+  echo "dummy 2.0.0 1.3" >"$PROJECT_DIR/.tool-versions"
 
-  run $ASDF_DIR/shims/dummy world hello
+  run "$ASDF_DIR/shims/dummy" world hello
   [ "$status" -eq 126 ]
   echo "$output" | grep -q "No preset version installed for command dummy" 2>/dev/null
   echo "$output" | grep -q "Please install a version by running one of the following:" 2>/dev/null
@@ -132,9 +132,9 @@ teardown() {
   run asdf install dummy 2.0.0
   run asdf install dummy 3.0
 
-  echo "dummy 1.0 3.0 2.0.0" >$PROJECT_DIR/.tool-versions
+  echo "dummy 1.0 3.0 2.0.0" >"$PROJECT_DIR/.tool-versions"
 
-  run $ASDF_DIR/shims/dummy world hello
+  run "$ASDF_DIR/shims/dummy" world hello
   [ "$status" -eq 0 ]
 
   echo "$output" | grep -q "This is Dummy 3.0! hello world" 2>/dev/null
@@ -143,10 +143,10 @@ teardown() {
 @test "shim exec should only use the first version found for a plugin" {
   run asdf install dummy 3.0
 
-  echo "dummy 3.0" >$PROJECT_DIR/.tool-versions
-  echo "dummy 1.0" >>$PROJECT_DIR/.tool-versions
+  echo "dummy 3.0" >"$PROJECT_DIR/.tool-versions"
+  echo "dummy 1.0" >>"$PROJECT_DIR/.tool-versions"
 
-  run $ASDF_DIR/shims/dummy world hello
+  run "$ASDF_DIR/shims/dummy" world hello
   [ "$status" -eq 0 ]
 
   echo "$output" | grep -q "This is Dummy 3.0! hello world" 2>/dev/null
@@ -154,40 +154,40 @@ teardown() {
 
 @test "shim exec should determine correct executable on two projects using different plugins that provide the same tool" {
   # Another fake plugin with 'dummy' executable
-  cp -rf $ASDF_DIR/plugins/dummy $ASDF_DIR/plugins/mummy
-  sed -i -e 's/Dummy/Mummy/' $ASDF_DIR/plugins/mummy/bin/install
+  cp -rf "$ASDF_DIR/plugins/dummy" "$ASDF_DIR/plugins/mummy"
+  sed -i -e 's/Dummy/Mummy/' "$ASDF_DIR/plugins/mummy/bin/install"
 
   run asdf install mummy 3.0
   run asdf install dummy 1.0
 
-  mkdir $PROJECT_DIR/{A,B}
-  echo "dummy 1.0" >$PROJECT_DIR/A/.tool-versions
-  echo "mummy 3.0" >$PROJECT_DIR/B/.tool-versions
+  mkdir "$PROJECT_DIR"/{A,B}
+  echo "dummy 1.0" >"$PROJECT_DIR/A/.tool-versions"
+  echo "mummy 3.0" >"$PROJECT_DIR/B/.tool-versions"
 
-  cd $PROJECT_DIR/A
-  run $ASDF_DIR/shims/dummy world hello
+  cd "$PROJECT_DIR"/A
+  run "$ASDF_DIR/shims/dummy" world hello
   [ "$output" = "This is Dummy 1.0! hello world" ]
   [ "$status" -eq 0 ]
 
-  cd $PROJECT_DIR/B
-  run $ASDF_DIR/shims/dummy world hello
+  cd "$PROJECT_DIR"/B
+  run "$ASDF_DIR/shims/dummy" world hello
   [ "$output" = "This is Mummy 3.0! hello world" ]
   [ "$status" -eq 0 ]
 }
 
 @test "shim exec should determine correct executable on a project with two plugins set that provide the same tool" {
   # Another fake plugin with 'dummy' executable
-  cp -rf $ASDF_DIR/plugins/dummy $ASDF_DIR/plugins/mummy
-  sed -i -e 's/Dummy/Mummy/' $ASDF_DIR/plugins/mummy/bin/install
+  cp -rf "$ASDF_DIR/plugins/dummy" "$ASDF_DIR/plugins/mummy"
+  sed -i -e 's/Dummy/Mummy/' "$ASDF_DIR/plugins/mummy/bin/install"
 
   run asdf install dummy 1.0
   run asdf install mummy 3.0
 
-  echo "dummy 2.0.0" >$PROJECT_DIR/.tool-versions
-  echo "mummy 3.0" >>$PROJECT_DIR/.tool-versions
-  echo "dummy 1.0" >>$PROJECT_DIR/.tool-versions
+  echo "dummy 2.0.0" >"$PROJECT_DIR/.tool-versions"
+  echo "mummy 3.0" >>"$PROJECT_DIR/.tool-versions"
+  echo "dummy 1.0" >>"$PROJECT_DIR/.tool-versions"
 
-  run $ASDF_DIR/shims/dummy world hello
+  run "$ASDF_DIR/shims/dummy" world hello
   [ "$output" = "This is Mummy 3.0! hello world" ]
   [ "$status" -eq 0 ]
 }
@@ -195,11 +195,11 @@ teardown() {
 @test "shim exec should fallback to system executable when specified version is system" {
   run asdf install dummy 1.0
 
-  echo "dummy system" >$PROJECT_DIR/.tool-versions
+  echo "dummy system" >"$PROJECT_DIR/.tool-versions"
 
-  mkdir $PROJECT_DIR/foo/
-  echo "echo System" >$PROJECT_DIR/foo/dummy
-  chmod +x $PROJECT_DIR/foo/dummy
+  mkdir "$PROJECT_DIR/foo/"
+  echo "echo System" >"$PROJECT_DIR/foo/dummy"
+  chmod +x "$PROJECT_DIR/foo/dummy"
 
   run env "PATH=$PATH:$PROJECT_DIR/foo" "$ASDF_DIR/shims/dummy" hello
   [ "$output" = "System" ]
@@ -214,21 +214,21 @@ teardown() {
   echo "echo System" >"$CUSTOM_DUMMY_BIN_PATH/dummy"
   chmod +x "$CUSTOM_DUMMY_BIN_PATH/dummy"
 
-  echo "dummy path:$CUSTOM_DUMMY_PATH" >$PROJECT_DIR/.tool-versions
+  echo "dummy path:$CUSTOM_DUMMY_PATH" >"$PROJECT_DIR/.tool-versions"
 
-  run $ASDF_DIR/shims/dummy hello
+  run "$ASDF_DIR/shims/dummy" hello
   [ "$output" = "System" ]
 }
 
 @test "shim exec should execute system if set first" {
   run asdf install dummy 2.0.0
 
-  echo "dummy system" >$PROJECT_DIR/.tool-versions
-  echo "dummy 2.0.0" >>$PROJECT_DIR/.tool-versions
+  echo "dummy system" >"$PROJECT_DIR/.tool-versions"
+  echo "dummy 2.0.0" >>"$PROJECT_DIR/.tool-versions"
 
-  mkdir $PROJECT_DIR/foo/
-  echo "echo System" >$PROJECT_DIR/foo/dummy
-  chmod +x $PROJECT_DIR/foo/dummy
+  mkdir "$PROJECT_DIR/foo/"
+  echo "echo System" >"$PROJECT_DIR/foo/dummy"
+  chmod +x "$PROJECT_DIR/foo/dummy"
 
   run env "PATH=$PATH:$PROJECT_DIR/foo" "$ASDF_DIR/shims/dummy" hello
   [ "$output" = "System" ]
@@ -242,8 +242,8 @@ teardown() {
   chmod +x "$ASDF_DIR/plugins/dummy/shims/foo"
   run asdf reshim dummy 2.0.0
 
-  echo "dummy 2.0.0" >$PROJECT_DIR/.tool-versions
-  run $ASDF_DIR/shims/foo
+  echo "dummy 2.0.0" >"$PROJECT_DIR/.tool-versions"
+  run "$ASDF_DIR/shims/foo"
   [ "$output" = "sourced custom" ]
 }
 
@@ -255,8 +255,8 @@ teardown() {
   chmod +x "$ASDF_DIR/plugins/dummy/shims/foo"
   run asdf reshim dummy 2.0.0
 
-  echo "dummy 2.0.0" >$PROJECT_DIR/.tool-versions
-  run $ASDF_DIR/shims/foo
+  echo "dummy 2.0.0" >"$PROJECT_DIR/.tool-versions"
+  run "$ASDF_DIR/shims/foo"
   [ "$output" = "$ASDF_DIR/installs/dummy/2.0.0/foo custom" ]
 }
 
@@ -268,11 +268,11 @@ teardown() {
   chmod +x "$ASDF_DIR/plugins/dummy/shims/foo"
   run asdf reshim dummy 2.0.0
 
-  echo "dummy system" >$PROJECT_DIR/.tool-versions
+  echo "dummy system" >"$PROJECT_DIR/.tool-versions"
 
-  mkdir $PROJECT_DIR/sys/
-  echo 'echo x$FOO System' >$PROJECT_DIR/sys/foo
-  chmod +x $PROJECT_DIR/sys/foo
+  mkdir "$PROJECT_DIR/sys/"
+  echo 'echo x$FOO System' >"$PROJECT_DIR/sys/foo"
+  chmod +x "$PROJECT_DIR/sys/foo"
 
   run env "PATH=$PATH:$PROJECT_DIR/sys" "$ASDF_DIR/shims/foo"
   [ "$output" = "x System" ]
@@ -281,53 +281,53 @@ teardown() {
 @test "shim exec should prepend the plugin paths on execution" {
   run asdf install dummy 2.0.0
 
-  mkdir $ASDF_DIR/plugins/dummy/shims
-  echo 'which dummy' >$ASDF_DIR/plugins/dummy/shims/foo
-  chmod +x $ASDF_DIR/plugins/dummy/shims/foo
+  mkdir "$ASDF_DIR/plugins/dummy/shims"
+  echo 'which dummy' >"$ASDF_DIR/plugins/dummy/shims/foo"
+  chmod +x "$ASDF_DIR/plugins/dummy/shims/foo"
   run asdf reshim dummy 2.0.0
 
-  echo "dummy 2.0.0" >$PROJECT_DIR/.tool-versions
+  echo "dummy 2.0.0" >"$PROJECT_DIR/.tool-versions"
 
-  run $ASDF_DIR/shims/foo
+  run "$ASDF_DIR/shims/foo"
   [ "$output" = "$ASDF_DIR/installs/dummy/2.0.0/bin/dummy" ]
 }
 
 @test "shim exec should be able to find other shims in path" {
-  cp -rf $ASDF_DIR/plugins/dummy $ASDF_DIR/plugins/gummy
+  cp -rf "$ASDF_DIR/plugins/dummy" "$ASDF_DIR/plugins/gummy"
 
-  echo "dummy 2.0.0" >$PROJECT_DIR/.tool-versions
-  echo "gummy 2.0.0" >>$PROJECT_DIR/.tool-versions
+  echo "dummy 2.0.0" >"$PROJECT_DIR/.tool-versions"
+  echo "gummy 2.0.0" >>"$PROJECT_DIR/.tool-versions"
 
   run asdf install
 
-  mkdir $ASDF_DIR/plugins/{dummy,gummy}/shims
+  mkdir "$ASDF_DIR/plugins/"{dummy,gummy}/shims
 
-  echo 'which dummy' >$ASDF_DIR/plugins/dummy/shims/foo
-  chmod +x $ASDF_DIR/plugins/dummy/shims/foo
+  echo 'which dummy' >"$ASDF_DIR/plugins/dummy/shims/foo"
+  chmod +x "$ASDF_DIR/plugins/dummy/shims/foo"
 
-  echo 'which gummy' >$ASDF_DIR/plugins/dummy/shims/bar
-  chmod +x $ASDF_DIR/plugins/dummy/shims/bar
+  echo 'which gummy' >"$ASDF_DIR/plugins/dummy/shims/bar"
+  chmod +x "$ASDF_DIR/plugins/dummy/shims/bar"
 
-  touch $ASDF_DIR/plugins/gummy/shims/gummy
-  chmod +x $ASDF_DIR/plugins/gummy/shims/gummy
+  touch "$ASDF_DIR/plugins/gummy/shims/gummy"
+  chmod +x "$ASDF_DIR/plugins/gummy/shims/gummy"
 
   run asdf reshim
 
-  run $ASDF_DIR/shims/foo
+  run "$ASDF_DIR/shims/foo"
   [ "$output" = "$ASDF_DIR/installs/dummy/2.0.0/bin/dummy" ]
 
-  run $ASDF_DIR/shims/bar
+  run "$ASDF_DIR/shims/bar"
   [ "$output" = "$ASDF_DIR/shims/gummy" ]
 }
 
 @test "shim exec should remove shim_path from path on system version execution" {
   run asdf install dummy 2.0.0
 
-  echo "dummy system" >$PROJECT_DIR/.tool-versions
+  echo "dummy system" >"$PROJECT_DIR/.tool-versions"
 
-  mkdir $PROJECT_DIR/sys/
-  echo 'which dummy' >$PROJECT_DIR/sys/dummy
-  chmod +x $PROJECT_DIR/sys/dummy
+  mkdir "$PROJECT_DIR/sys/"
+  echo 'which dummy' >"$PROJECT_DIR/sys/dummy"
+  chmod +x "$PROJECT_DIR/sys/dummy"
 
   run env "PATH=$PATH:$PROJECT_DIR/sys" "$ASDF_DIR/shims/dummy"
   echo "$status $output"
@@ -340,7 +340,7 @@ teardown() {
   echo "legacy_version_file = yes" >"$HOME/.asdfrc"
   echo "2.0.0" >"$PROJECT_DIR/.dummy-version"
 
-  run $ASDF_DIR/shims/dummy world hello
+  run "$ASDF_DIR/shims/dummy" world hello
   [ "$output" = "This is Dummy 2.0.0! hello world" ]
 }
 
@@ -354,19 +354,19 @@ teardown() {
   exec_path="$ASDF_DIR/plugins/dummy/bin/list-bin-paths"
   custom_path="$ASDF_DIR/installs/dummy/1.0/custom"
 
-  echo "echo bin custom" >$exec_path
-  chmod +x $exec_path
+  echo "echo bin custom" >"$exec_path"
+  chmod +x "$exec_path"
 
   run asdf install dummy 1.0
-  echo "dummy 1.0" >$PROJECT_DIR/.tool-versions
+  echo "dummy 1.0" >"$PROJECT_DIR/.tool-versions"
 
-  mkdir $custom_path
-  echo "echo CUSTOM" >$custom_path/foo
-  chmod +x $custom_path/foo
+  mkdir "$custom_path"
+  echo "echo CUSTOM" >"$custom_path/foo"
+  chmod +x "$custom_path/foo"
 
   run asdf reshim dummy 1.0
 
-  run $ASDF_DIR/shims/foo
+  run "$ASDF_DIR/shims/foo"
   [ "$output" = "CUSTOM" ]
 }
 
@@ -376,16 +376,16 @@ teardown() {
   exec_path="$ASDF_DIR/plugins/dummy/bin/exec-path"
   custom_dummy="$ASDF_DIR/installs/dummy/1.0/custom/dummy"
 
-  echo "echo custom/dummy" >$exec_path
-  chmod +x $exec_path
+  echo "echo custom/dummy" >"$exec_path"
+  chmod +x "$exec_path"
 
   mkdir "$(dirname "$custom_dummy")"
   echo "echo CUSTOM" >"$custom_dummy"
   chmod +x "$custom_dummy"
 
-  echo "dummy 1.0" >$PROJECT_DIR/.tool-versions
+  echo "dummy 1.0" >"$PROJECT_DIR/.tool-versions"
 
-  run $ASDF_DIR/shims/dummy
+  run "$ASDF_DIR/shims/dummy"
   [ "$output" = "CUSTOM" ]
 }
 
@@ -397,21 +397,21 @@ teardown() {
   echo 'echo $3 # always same path' >"$exec_path"
   chmod +x "$exec_path"
 
-  echo "dummy 1.0" >$PROJECT_DIR/.tool-versions
+  echo "dummy 1.0" >"$PROJECT_DIR/.tool-versions"
 
-  run $ASDF_DIR/shims/dummy
+  run "$ASDF_DIR/shims/dummy"
   [ "$output" = "This is Dummy 1.0!" ]
 }
 
 @test "shim exec executes configured pre-hook" {
   run asdf install dummy 1.0
-  echo dummy 1.0 >$PROJECT_DIR/.tool-versions
+  echo dummy 1.0 >"$PROJECT_DIR/.tool-versions"
 
-  cat >$HOME/.asdfrc <<-'EOM'
+  cat >"$HOME/.asdfrc" <<-'EOM'
 pre_dummy_dummy = echo PRE $version $1 $2
 EOM
 
-  run $ASDF_DIR/shims/dummy hello world
+  run "$ASDF_DIR/shims/dummy" hello world
   [ "$status" -eq 0 ]
   echo "$output" | grep "PRE 1.0 hello world"
   echo "$output" | grep "This is Dummy 1.0! world hello"
@@ -419,14 +419,14 @@ EOM
 
 @test "shim exec doesnt execute command if pre-hook failed" {
   run asdf install dummy 1.0
-  echo dummy 1.0 >$PROJECT_DIR/.tool-versions
+  echo dummy 1.0 >"$PROJECT_DIR/.tool-versions"
 
-  mkdir $HOME/hook
+  mkdir "$HOME/hook"
   pre_cmd="$HOME/hook/pre"
   echo 'echo $* && false' >"$pre_cmd"
   chmod +x "$pre_cmd"
 
-  cat >$HOME/.asdfrc <<'EOM'
+  cat >"$HOME/.asdfrc" <<'EOM'
 pre_dummy_dummy = pre $1 no $plugin_name $2
 EOM
 
@@ -439,11 +439,11 @@ EOM
 @test "asdf exec should not crash when POSIXLY_CORRECT=1" {
   export POSIXLY_CORRECT=1
 
-  echo "dummy 1.0" >$PROJECT_DIR/.tool-versions
+  echo "dummy 1.0" >"$PROJECT_DIR/.tool-versions"
   run asdf install
 
   run asdf exec dummy world hello
-  echo $output
+  echo "$output"
   [ "$output" = "This is Dummy 1.0! hello world" ]
   [ "$status" -eq 0 ]
 }
diff --git a/test/shim_versions_command.bats b/test/shim_versions_command.bats
index ab2e74f3..e4ed706c 100644
--- a/test/shim_versions_command.bats
+++ b/test/shim_versions_command.bats
@@ -16,7 +16,7 @@ teardown() {
 }
 
 @test "shim_versions_command should list plugins and versions where command is available" {
-  cd $PROJECT_DIR
+  cd "$PROJECT_DIR"
   run asdf install dummy 3.0
   run asdf install dummy 1.0
   run asdf reshim dummy
diff --git a/test/uninstall_command.bats b/test/uninstall_command.bats
index 775a5564..e98325d3 100644
--- a/test/uninstall_command.bats
+++ b/test/uninstall_command.bats
@@ -31,9 +31,9 @@ teardown() {
 @test "uninstall_command should invoke the plugin bin/uninstall if available" {
   run asdf install dummy 1.1.0
   [ "$status" -eq 0 ]
-  mkdir -p $ASDF_DIR/plugins/dummy/bin
-  echo "echo custom uninstall" >$ASDF_DIR/plugins/dummy/bin/uninstall
-  chmod 755 $ASDF_DIR/plugins/dummy/bin/uninstall
+  mkdir -p "$ASDF_DIR/plugins/dummy/bin"
+  echo "echo custom uninstall" >"$ASDF_DIR/plugins/dummy/bin/uninstall"
+  chmod 755 "$ASDF_DIR/plugins/dummy/bin/uninstall"
   run asdf uninstall dummy 1.1.0
   [ "$output" = "custom uninstall" ]
   [ "$status" -eq 0 ]
@@ -66,9 +66,9 @@ teardown() {
   [ -f "$ASDF_DIR/installs/dummy/1.1.0/bin/dummy" ]
 
   run asdf uninstall dummy 1.0.0
-  run grep "asdf-plugin: dummy 1.1.0" $ASDF_DIR/shims/dummy
+  run grep "asdf-plugin: dummy 1.1.0" "$ASDF_DIR/shims/dummy"
   [ "$status" -eq 0 ]
-  run grep "asdf-plugin: dummy 1.0.0" $ASDF_DIR/shims/dummy
+  run grep "asdf-plugin: dummy 1.0.0" "$ASDF_DIR/shims/dummy"
   [ "$status" -eq 1 ]
 }
 
@@ -84,7 +84,7 @@ teardown() {
 }
 
 @test "uninstall command executes configured pre hook" {
-  cat >$HOME/.asdfrc <<-'EOM'
+  cat >"$HOME/.asdfrc" <<-'EOM'
 pre_asdf_uninstall_dummy = echo will uninstall dummy $1
 EOM
 
@@ -94,12 +94,12 @@ EOM
 }
 
 @test "uninstall command executes configured post hook" {
-  cat >$HOME/.asdfrc <<-'EOM'
+  cat >"$HOME/.asdfrc" <<-'EOM'
 post_asdf_uninstall_dummy = echo removed dummy $1
 EOM
 
   run asdf install dummy 1.0.0
   run asdf uninstall dummy 1.0.0
-  echo $output
+  echo "$output"
   [ "$output" = "removed dummy 1.0.0" ]
 }
diff --git a/test/update_command.bats b/test/update_command.bats
index cae5a3cf..13c259fe 100644
--- a/test/update_command.bats
+++ b/test/update_command.bats
@@ -60,14 +60,14 @@ teardown() {
 }
 
 @test "asdf update is a noop for when updates are disabled" {
-  touch $ASDF_DIR/asdf_updates_disabled
+  touch "$ASDF_DIR/asdf_updates_disabled"
   run asdf update
   [ "$status" -eq 42 ]
   [ "$(echo -e "Update command disabled. Please use the package manager that you used to install asdf to upgrade asdf.")" = "$output" ]
 }
 
 @test "asdf update is a noop for non-git repos" {
-  rm -rf $ASDF_DIR/.git/
+  rm -rf "$ASDF_DIR/.git/"
   run asdf update
   [ "$status" -eq 42 ]
   [ "$(echo -e "Update command disabled. Please use the package manager that you used to install asdf to upgrade asdf.")" = "$output" ]
diff --git a/test/utils.bats b/test/utils.bats
index 2cbf1dcc..e8a60ba2 100644
--- a/test/utils.bats
+++ b/test/utils.bats
@@ -11,7 +11,7 @@ setup() {
   PROJECT_DIR="$HOME/project"
   mkdir -p "$PROJECT_DIR"
 
-  cd $HOME
+  cd "$HOME"
 }
 
 teardown() {
@@ -42,7 +42,7 @@ teardown() {
   run get_download_path foo version "1.0.0"
   [ "$status" -eq 0 ]
   download_path=${output#$HOME/}
-  echo $download_path
+  echo "$download_path"
   [ "$download_path" = ".asdf/downloads/foo/1.0.0" ]
 }
 
@@ -83,15 +83,15 @@ teardown() {
 }
 
 @test "check_if_version_exists should be noop if version is system" {
-  mkdir -p $ASDF_DIR/plugins/foo
+  mkdir -p "$ASDF_DIR/plugins/foo"
   run check_if_version_exists "foo" "system"
   [ "$status" -eq 0 ]
   [ "$output" = "" ]
 }
 
 @test "check_if_version_exists should be ok for ref:version install" {
-  mkdir -p $ASDF_DIR/plugins/foo
-  mkdir -p $ASDF_DIR/installs/foo/ref-master
+  mkdir -p "$ASDF_DIR/plugins/foo"
+  mkdir -p "$ASDF_DIR/installs/foo/ref-master"
   run check_if_version_exists "foo" "ref:master"
   [ "$status" -eq 0 ]
   [ "$output" = "" ]
@@ -110,8 +110,8 @@ teardown() {
 }
 
 @test "parse_asdf_version_file should output version" {
-  echo "dummy 0.1.0" >$PROJECT_DIR/.tool-versions
-  run parse_asdf_version_file $PROJECT_DIR/.tool-versions dummy
+  echo "dummy 0.1.0" >"$PROJECT_DIR/.tool-versions"
+  run parse_asdf_version_file "$PROJECT_DIR/.tool-versions" dummy
   [ "$status" -eq 0 ]
   [ "$output" = "0.1.0" ]
 }
@@ -119,7 +119,7 @@ teardown() {
 @test "parse_asdf_version_file should output path on project with spaces" {
   PROJECT_DIR="$PROJECT_DIR/outer space"
   mkdir -p "$PROJECT_DIR"
-  cd $outer
+
   echo "dummy 0.1.0" >"$PROJECT_DIR/.tool-versions"
   run parse_asdf_version_file "$PROJECT_DIR/.tool-versions" dummy
   [ "$status" -eq 0 ]
@@ -127,24 +127,24 @@ teardown() {
 }
 
 @test "parse_asdf_version_file should output path version with spaces" {
-  echo "dummy path:/some/dummy path" >$PROJECT_DIR/.tool-versions
-  run parse_asdf_version_file $PROJECT_DIR/.tool-versions dummy
+  echo "dummy path:/some/dummy path" >"$PROJECT_DIR/.tool-versions"
+  run parse_asdf_version_file "$PROJECT_DIR/.tool-versions" dummy
   [ "$status" -eq 0 ]
   [ "$output" = "path:/some/dummy path" ]
 }
 
 @test "parse_asdf_version_file should output path version with tilda" {
-  echo "dummy path:~/some/dummy path" >$PROJECT_DIR/.tool-versions
-  run parse_asdf_version_file $PROJECT_DIR/.tool-versions dummy
+  echo "dummy path:~/some/dummy path" >"$PROJECT_DIR/.tool-versions"
+  run parse_asdf_version_file "$PROJECT_DIR/.tool-versions" dummy
   [ "$status" -eq 0 ]
   [ "$output" = "path:$HOME/some/dummy path" ]
 }
 
 @test "find_versions should return .tool-versions if legacy is disabled" {
-  echo "dummy 0.1.0" >$PROJECT_DIR/.tool-versions
-  echo "0.2.0" >$PROJECT_DIR/.dummy-version
+  echo "dummy 0.1.0" >"$PROJECT_DIR/.tool-versions"
+  echo "0.2.0" >"$PROJECT_DIR/.dummy-version"
 
-  run find_versions "dummy" $PROJECT_DIR
+  run find_versions "dummy" "$PROJECT_DIR"
   [ "$status" -eq 0 ]
   [ "$output" = "0.1.0|$PROJECT_DIR/.tool-versions" ]
 }
@@ -154,16 +154,16 @@ teardown() {
   echo "dummy 0.1.0" >"$HOME/.tool-versions"
   echo "0.2.0" >"$PROJECT_DIR/.dummy-version"
 
-  run find_versions "dummy" $PROJECT_DIR
+  run find_versions "dummy" "$PROJECT_DIR"
   [ "$status" -eq 0 ]
   [ "$output" = "0.2.0|$PROJECT_DIR/.dummy-version" ]
 }
 
 @test "find_versions skips .tool-version file that don't list the plugin" {
-  echo "dummy 0.1.0" >$HOME/.tool-versions
-  echo "another_plugin 0.3.0" >$PROJECT_DIR/.tool-versions
+  echo "dummy 0.1.0" >"$HOME/.tool-versions"
+  echo "another_plugin 0.3.0" >"$PROJECT_DIR/.tool-versions"
 
-  run find_versions "dummy" $PROJECT_DIR
+  run find_versions "dummy" "$PROJECT_DIR"
   [ "$status" -eq 0 ]
   [ "$output" = "0.1.0|$HOME/.tool-versions" ]
 }
@@ -174,7 +174,7 @@ teardown() {
   echo "legacy_version_file = yes" >"$HOME/.asdfrc"
   rm "$ASDF_DIR/plugins/dummy/bin/list-legacy-filenames"
 
-  run find_versions "dummy" $PROJECT_DIR
+  run find_versions "dummy" "$PROJECT_DIR"
   [ "$status" -eq 0 ]
   [ "$output" = "0.1.0|$HOME/.tool-versions" ]
 }
@@ -182,9 +182,9 @@ teardown() {
 @test "find_versions should return the version set by environment variable" {
   export ASDF_DUMMY_VERSION=0.2.0
 
-  run find_versions "dummy" $PROJECT_DIR
+  run find_versions "dummy" "$PROJECT_DIR"
   [ "$status" -eq 0 ]
-  echo $output
+  echo "$output"
   [ "$output" = "0.2.0|ASDF_DUMMY_VERSION environment variable" ]
 }
 
@@ -220,9 +220,9 @@ teardown() {
 
 @test "find_versions should return \$ASDF_DEFAULT_TOOL_VERSIONS_FILENAME if set" {
   ASDF_DEFAULT_TOOL_VERSIONS_FILENAME="$PROJECT_DIR/global-tool-versions"
-  echo "dummy 0.1.0" >$ASDF_DEFAULT_TOOL_VERSIONS_FILENAME
+  echo "dummy 0.1.0" >"$ASDF_DEFAULT_TOOL_VERSIONS_FILENAME"
 
-  run find_versions "dummy" $PROJECT_DIR
+  run find_versions "dummy" "$PROJECT_DIR"
   [ "$status" -eq 0 ]
   [ "$output" = "0.1.0|$ASDF_DEFAULT_TOOL_VERSIONS_FILENAME" ]
 }
@@ -233,13 +233,13 @@ teardown() {
   echo "dummy 0.1.0" >"$HOME/.dummy-version"
   echo "legacy_version_file = yes" >"$HOME/.asdfrc"
 
-  run find_versions "dummy" $PROJECT_DIR
+  run find_versions "dummy" "$PROJECT_DIR"
   [ "$status" -eq 0 ]
   [[ "$output" =~ "0.1.0|$HOME/.dummy-version" ]]
 }
 
 @test "get_preset_version_for returns the current version" {
-  cd $PROJECT_DIR
+  cd "$PROJECT_DIR"
   echo "dummy 0.2.0" >.tool-versions
   run get_preset_version_for "dummy"
   [ "$status" -eq 0 ]
@@ -247,16 +247,16 @@ teardown() {
 }
 
 @test "get_preset_version_for returns the global version from home when project is outside of home" {
-  echo "dummy 0.1.0" >$HOME/.tool-versions
+  echo "dummy 0.1.0" >"$HOME/.tool-versions"
   PROJECT_DIR=$BASE_DIR/project
-  mkdir -p $PROJECT_DIR
+  mkdir -p "$PROJECT_DIR"
   run get_preset_version_for "dummy"
   [ "$status" -eq 0 ]
   [ "$output" = "0.1.0" ]
 }
 
 @test "get_preset_version_for returns the tool version from env if ASDF_{TOOL}_VERSION is defined" {
-  cd $PROJECT_DIR
+  cd "$PROJECT_DIR"
   echo "dummy 0.2.0" >.tool-versions
   ASDF_DUMMY_VERSION=3.0.0 run get_preset_version_for "dummy"
   [ "$status" -eq 0 ]
@@ -264,40 +264,40 @@ teardown() {
 }
 
 @test "get_preset_version_for should return branch reference version" {
-  cd $PROJECT_DIR
-  echo "dummy ref:master" >$PROJECT_DIR/.tool-versions
+  cd "$PROJECT_DIR"
+  echo "dummy ref:master" >"$PROJECT_DIR/.tool-versions"
   run get_preset_version_for "dummy"
   [ "$status" -eq 0 ]
   [ "$output" = "ref:master" ]
 }
 
 @test "get_preset_version_for should return path version" {
-  cd $PROJECT_DIR
-  echo "dummy path:/some/place with spaces" >$PROJECT_DIR/.tool-versions
+  cd "$PROJECT_DIR"
+  echo "dummy path:/some/place with spaces" >"$PROJECT_DIR/.tool-versions"
   run get_preset_version_for "dummy"
   [ "$status" -eq 0 ]
   [ "$output" = "path:/some/place with spaces" ]
 }
 
 @test "get_preset_version_for should return path version with tilda" {
-  cd $PROJECT_DIR
-  echo "dummy path:~/some/place with spaces" >$PROJECT_DIR/.tool-versions
+  cd "$PROJECT_DIR"
+  echo "dummy path:~/some/place with spaces" >"$PROJECT_DIR/.tool-versions"
   run get_preset_version_for "dummy"
   [ "$status" -eq 0 ]
   [ "$output" = "path:$HOME/some/place with spaces" ]
 }
 
 @test "get_executable_path for system version should return system path" {
-  mkdir -p $ASDF_DIR/plugins/foo
+  mkdir -p "$ASDF_DIR/plugins/foo"
   run get_executable_path "foo" "system" "ls"
   [ "$status" -eq 0 ]
   [ "$output" = "$(which ls)" ]
 }
 
 @test "get_executable_path for system version should not use asdf shims" {
-  mkdir -p $ASDF_DIR/plugins/foo
-  touch $ASDF_DIR/shims/dummy_executable
-  chmod +x $ASDF_DIR/shims/dummy_executable
+  mkdir -p "$ASDF_DIR/plugins/foo"
+  touch "$ASDF_DIR/shims/dummy_executable"
+  chmod +x "$ASDF_DIR/shims/dummy_executable"
 
   run which dummy_executable
   [ "$status" -eq 0 ]
@@ -331,8 +331,8 @@ teardown() {
 }
 
 @test "find_tool_versions will find a .tool-versions path if it exists in current directory" {
-  echo "dummy 0.1.0" >$PROJECT_DIR/.tool-versions
-  cd $PROJECT_DIR
+  echo "dummy 0.1.0" >"$PROJECT_DIR/.tool-versions"
+  cd "$PROJECT_DIR"
 
   run find_tool_versions
   [ "$status" -eq 0 ]
@@ -340,9 +340,9 @@ teardown() {
 }
 
 @test "find_tool_versions will find a .tool-versions path if it exists in parent directory" {
-  echo "dummy 0.1.0" >$PROJECT_DIR/.tool-versions
-  mkdir -p $PROJECT_DIR/child
-  cd $PROJECT_DIR/child
+  echo "dummy 0.1.0" >"$PROJECT_DIR/.tool-versions"
+  mkdir -p "$PROJECT_DIR/child"
+  cd "$PROJECT_DIR"/child
 
   run find_tool_versions
   [ "$status" -eq 0 ]
@@ -366,7 +366,7 @@ teardown() {
 
 @test "resolve_symlink converts the symlink path to the real file path" {
   touch foo
-  ln -s $PWD/foo bar
+  ln -s "$PWD/foo" bar
 
   run resolve_symlink bar
   [ "$status" -eq 0 ]
@@ -444,17 +444,17 @@ EOF
 }
 
 @test "with_shim_executable doesn't crash when executable names contain dashes" {
-  cd $PROJECT_DIR
-  echo "dummy 0.1.0" >$PROJECT_DIR/.tool-versions
-  mkdir -p $ASDF_DIR/installs/dummy/0.1.0/bin
-  touch $ASDF_DIR/installs/dummy/0.1.0/bin/test-dash
-  chmod +x $ASDF_DIR/installs/dummy/0.1.0/bin/test-dash
+  cd "$PROJECT_DIR"
+  echo "dummy 0.1.0" >"$PROJECT_DIR/.tool-versions"
+  mkdir -p "$ASDF_DIR/installs/dummy/0.1.0/bin"
+  touch "$ASDF_DIR/installs/dummy/0.1.0/bin/test-dash"
+  chmod +x "$ASDF_DIR/installs/dummy/0.1.0/bin/test-dash"
   run asdf reshim dummy 0.1.0
 
   message="callback invoked"
 
   function callback() {
-    echo $message
+    echo "$message"
   }
 
   run with_shim_executable test-dash callback
diff --git a/test/version_commands.bats b/test/version_commands.bats
index 8ce5f515..a6ecc40a 100644
--- a/test/version_commands.bats
+++ b/test/version_commands.bats
@@ -21,10 +21,10 @@ setup() {
   CHILD_DIR="$PROJECT_DIR/child-dir"
   mkdir -p "$CHILD_DIR"
 
-  cd $PROJECT_DIR
+  cd "$PROJECT_DIR"
 
   # asdf lib needed to run asdf.sh
-  cp -rf $BATS_TEST_DIRNAME/../{bin,lib} $ASDF_DIR/
+  cp -rf "$BATS_TEST_DIRNAME"/../{bin,lib} "$ASDF_DIR/"
 }
 
 teardown() {
@@ -111,7 +111,7 @@ teardown() {
 }
 
 @test "local should not create a duplicate .tool-versions file if such file exists" {
-  echo 'dummy 1.0.0' >>$PROJECT_DIR/.tool-versions
+  echo 'dummy 1.0.0' >>"$PROJECT_DIR/.tool-versions"
 
   run asdf local "dummy" "1.1.0"
   [ "$status" -eq 0 ]
@@ -119,7 +119,7 @@ teardown() {
 }
 
 @test "local should overwrite the existing version if it's set" {
-  echo 'dummy 1.0.0' >>$PROJECT_DIR/.tool-versions
+  echo 'dummy 1.0.0' >>"$PROJECT_DIR/.tool-versions"
 
   run asdf local "dummy" "1.1.0"
   [ "$status" -eq 0 ]
@@ -127,7 +127,7 @@ teardown() {
 }
 
 @test "local should append trailing newline before appending new version when missing" {
-  echo -n 'foobar 1.0.0' >>$PROJECT_DIR/.tool-versions
+  echo -n 'foobar 1.0.0' >>"$PROJECT_DIR/.tool-versions"
 
   run asdf local "dummy" "1.1.0"
   [ "$status" -eq 0 ]
@@ -135,7 +135,7 @@ teardown() {
 }
 
 @test "local should not append trailing newline before appending new version when one present" {
-  echo 'foobar 1.0.0' >>$PROJECT_DIR/.tool-versions
+  echo 'foobar 1.0.0' >>"$PROJECT_DIR/.tool-versions"
 
   run asdf local "dummy" "1.1.0"
   [ "$status" -eq 0 ]
@@ -149,7 +149,7 @@ teardown() {
 }
 
 @test "local should set a path:dir if dir exists " {
-  mkdir -p $PROJECT_DIR/local
+  mkdir -p "$PROJECT_DIR/local"
   run asdf local "dummy" "path:$PROJECT_DIR/local"
   [ "$status" -eq 0 ]
   [ "$(cat "$PROJECT_DIR/.tool-versions")" = "dummy path:$PROJECT_DIR/local" ]
@@ -174,24 +174,24 @@ teardown() {
 }
 
 @test "local -p/--parent should allow multiple versions" {
-  cd $CHILD_DIR
-  touch $PROJECT_DIR/.tool-versions
+  cd "$CHILD_DIR"
+  touch "$PROJECT_DIR/.tool-versions"
   run asdf local -p "dummy" "1.1.0" "1.0.0"
   [ "$status" -eq 0 ]
   [ "$(cat "$PROJECT_DIR/.tool-versions")" = "dummy 1.1.0 1.0.0" ]
 }
 
 @test "local -p/--parent should overwrite the existing version if it's set" {
-  cd $CHILD_DIR
-  echo 'dummy 1.0.0' >>$PROJECT_DIR/.tool-versions
+  cd "$CHILD_DIR"
+  echo 'dummy 1.0.0' >>"$PROJECT_DIR/.tool-versions"
   run asdf local -p "dummy" "1.1.0"
   [ "$status" -eq 0 ]
   [ "$(cat "$PROJECT_DIR/.tool-versions")" = "dummy 1.1.0" ]
 }
 
 @test "local -p/--parent should set the version if it's unset" {
-  cd $CHILD_DIR
-  touch $PROJECT_DIR/.tool-versions
+  cd "$CHILD_DIR"
+  touch "$PROJECT_DIR/.tool-versions"
   run asdf local -p "dummy" "1.1.0"
   [ "$status" -eq 0 ]
   [ "$(cat "$PROJECT_DIR/.tool-versions")" = "dummy 1.1.0" ]
@@ -246,14 +246,14 @@ teardown() {
 }
 
 @test "global should overwrite the existing version if it's set" {
-  echo 'dummy 1.0.0' >>$HOME/.tool-versions
+  echo 'dummy 1.0.0' >>"$HOME/.tool-versions"
   run asdf global "dummy" "1.1.0"
   [ "$status" -eq 0 ]
   [ "$(cat "$HOME/.tool-versions")" = "dummy 1.1.0" ]
 }
 
 @test "global should append trailing newline before appending new version when missing" {
-  echo -n 'foobar 1.0.0' >>$HOME/.tool-versions
+  echo -n 'foobar 1.0.0' >>"$HOME/.tool-versions"
 
   run asdf global "dummy" "1.1.0"
   [ "$status" -eq 0 ]
@@ -261,7 +261,7 @@ teardown() {
 }
 
 @test "global should not append trailing newline before appending new version when one present" {
-  echo 'foobar 1.0.0' >>$HOME/.tool-versions
+  echo 'foobar 1.0.0' >>"$HOME/.tool-versions"
 
   run asdf global "dummy" "1.1.0"
   [ "$status" -eq 0 ]
@@ -275,7 +275,7 @@ teardown() {
 }
 
 @test "global should set a path:dir if dir exists " {
-  mkdir -p $PROJECT_DIR/local
+  mkdir -p "$PROJECT_DIR/local"
   run asdf global "dummy" "path:$PROJECT_DIR/local"
   [ "$status" -eq 0 ]
   [ "$(cat "$HOME/.tool-versions")" = "dummy path:$PROJECT_DIR/local" ]
@@ -341,9 +341,9 @@ teardown() {
 }
 
 @test "global should preserve symlinks when setting versions" {
-  mkdir $HOME/other-dir
-  touch $HOME/other-dir/.tool-versions
-  ln -s other-dir/.tool-versions $HOME/.tool-versions
+  mkdir "$HOME/other-dir"
+  touch "$HOME/other-dir/.tool-versions"
+  ln -s other-dir/.tool-versions "$HOME/.tool-versions"
 
   run asdf global "dummy" "1.1.0"
   [ "$status" -eq 0 ]
@@ -352,9 +352,9 @@ teardown() {
 }
 
 @test "global should preserve symlinks when updating versions" {
-  mkdir $HOME/other-dir
-  touch $HOME/other-dir/.tool-versions
-  ln -s other-dir/.tool-versions $HOME/.tool-versions
+  mkdir "$HOME/other-dir"
+  touch "$HOME/other-dir/.tool-versions"
+  ln -s other-dir/.tool-versions "$HOME/.tool-versions"
 
   run asdf global "dummy" "1.1.0"
   run asdf global "dummy" "1.1.0"
@@ -465,28 +465,28 @@ false"
 }
 
 @test "[global - dummy_plugin] should support latest" {
-  echo 'dummy 1.0.0' >>$HOME/.tool-versions
+  echo 'dummy 1.0.0' >>"$HOME/.tool-versions"
   run asdf global "dummy" "1.0.0" "latest"
   [ "$status" -eq 0 ]
   [ "$(cat "$HOME/.tool-versions")" = "dummy 1.0.0 2.0.0" ]
 }
 
 @test "[global - dummy_legacy_plugin] should support latest" {
-  echo 'legacy-dummy 1.0.0' >>$HOME/.tool-versions
+  echo 'legacy-dummy 1.0.0' >>"$HOME/.tool-versions"
   run asdf global "legacy-dummy" "1.0.0" "latest"
   [ "$status" -eq 0 ]
   [ "$(cat "$HOME/.tool-versions")" = "legacy-dummy 1.0.0 5.1.0" ]
 }
 
 @test "[local - dummy_plugin] should support latest" {
-  echo 'dummy 1.0.0' >>$PROJECT_DIR/.tool-versions
+  echo 'dummy 1.0.0' >>"$PROJECT_DIR/.tool-versions"
   run asdf local "dummy" "1.0.0" "latest"
   [ "$status" -eq 0 ]
   [ "$(cat "$PROJECT_DIR/.tool-versions")" = "dummy 1.0.0 2.0.0" ]
 }
 
 @test "[local - dummy_legacy_plugin] should support latest" {
-  echo 'legacy-dummy 1.0.0' >>$PROJECT_DIR/.tool-versions
+  echo 'legacy-dummy 1.0.0' >>"$PROJECT_DIR/.tool-versions"
   run asdf local "legacy-dummy" "1.0.0" "latest"
   [ "$status" -eq 0 ]
   [ "$(cat "$PROJECT_DIR/.tool-versions")" = "legacy-dummy 1.0.0 5.1.0" ]
diff --git a/test/where_command.bats b/test/where_command.bats
index f92292a7..ddb2c32b 100644
--- a/test/where_command.bats
+++ b/test/where_command.bats
@@ -27,7 +27,7 @@ function teardown() {
 }
 
 @test "where shows install location of current version if no version specified" {
-  echo 'dummy 2.1' >>$HOME/.tool-versions
+  echo 'dummy 2.1' >>"$HOME/.tool-versions"
 
   run asdf where 'dummy'
 
@@ -36,7 +36,7 @@ function teardown() {
 }
 
 @test "where shows install location of first current version if not version specified and multiple current versions" {
-  echo 'dummy 2.1 1.0' >>$HOME/.tool-versions
+  echo 'dummy 2.1 1.0' >>"$HOME/.tool-versions"
   run asdf where 'dummy'
   [ "$status" -eq 0 ]
   [ "$output" = "$ASDF_DIR/installs/dummy/2.1" ]
diff --git a/test/which_command.bats b/test/which_command.bats
index a1908ee2..3dc708a9 100644
--- a/test/which_command.bats
+++ b/test/which_command.bats
@@ -18,7 +18,7 @@ teardown() {
 }
 
 @test "which should show dummy 1.0 main binary" {
-  cd $PROJECT_DIR
+  cd "$PROJECT_DIR"
 
   run asdf which "dummy"
   [ "$status" -eq 0 ]
@@ -26,7 +26,7 @@ teardown() {
 }
 
 @test "which should fail for unknown binary" {
-  cd $PROJECT_DIR
+  cd "$PROJECT_DIR"
 
   run asdf which "sunny"
   [ "$status" -eq 1 ]
@@ -34,7 +34,7 @@ teardown() {
 }
 
 @test "which should show dummy 1.0 other binary" {
-  cd $PROJECT_DIR
+  cd "$PROJECT_DIR"
 
   echo "echo bin bin/subdir" >"$ASDF_DIR/plugins/dummy/bin/list-bin-paths"
   chmod +x "$ASDF_DIR/plugins/dummy/bin/list-bin-paths"
@@ -46,12 +46,12 @@ teardown() {
 }
 
 @test "which should show path of system version" {
-  echo 'dummy system' >$PROJECT_DIR/.tool-versions
-  cd $PROJECT_DIR
+  echo 'dummy system' >"$PROJECT_DIR/.tool-versions"
+  cd "$PROJECT_DIR"
 
-  mkdir $PROJECT_DIR/sys
-  touch $PROJECT_DIR/sys/dummy
-  chmod +x $PROJECT_DIR/sys/dummy
+  mkdir "$PROJECT_DIR/sys"
+  touch "$PROJECT_DIR/sys/dummy"
+  chmod +x "$PROJECT_DIR/sys/dummy"
 
   run env "PATH=$PATH:$PROJECT_DIR/sys" asdf which "dummy"
   [ "$status" -eq 0 ]
@@ -59,8 +59,8 @@ teardown() {
 }
 
 @test "which report when missing executable on system version" {
-  echo 'dummy system' >$PROJECT_DIR/.tool-versions
-  cd $PROJECT_DIR
+  echo 'dummy system' >"$PROJECT_DIR/.tool-versions"
+  cd "$PROJECT_DIR"
 
   run asdf which "dummy"
   [ "$status" -eq 1 ]
@@ -68,7 +68,7 @@ teardown() {
 }
 
 @test "which should inform when no binary is found" {
-  cd $PROJECT_DIR
+  cd "$PROJECT_DIR"
 
   run asdf which "bazbat"
   [ "$status" -eq 1 ]
@@ -76,7 +76,7 @@ teardown() {
 }
 
 @test "which should use path returned by exec-path when present" {
-  cd $PROJECT_DIR
+  cd "$PROJECT_DIR"
   install_dummy_exec_path_script "dummy"
 
   run asdf which "dummy"
@@ -85,7 +85,7 @@ teardown() {
 }
 
 @test "which should return the path set by the legacy file" {
-  cd $PROJECT_DIR
+  cd "$PROJECT_DIR"
 
   echo 'dummy 1.0' >>"$HOME/.tool-versions"
   echo '1.1' >>"$PROJECT_DIR/.dummy-version"
@@ -98,8 +98,8 @@ teardown() {
 }
 
 @test "which should not return shim path" {
-  cd $PROJECT_DIR
-  echo 'dummy 1.0' >$PROJECT_DIR/.tool-versions
+  cd "$PROJECT_DIR"
+  echo 'dummy 1.0' >"$PROJECT_DIR/.tool-versions"
   rm "$ASDF_DIR/installs/dummy/1.0/bin/dummy"
 
   run env PATH="$PATH:$ASDF_DIR/shims" asdf which dummy