diff --git a/packages/audio/alsa-lib/package.mk b/packages/audio/alsa-lib/package.mk
index a69f5636c8..da8dda0bfc 100644
--- a/packages/audio/alsa-lib/package.mk
+++ b/packages/audio/alsa-lib/package.mk
@@ -7,7 +7,7 @@ PKG_VERSION="1.2.4"
 PKG_SHA256="f7554be1a56cdff468b58fc1c29b95b64864c590038dd309c7a978c7116908f7"
 PKG_LICENSE="GPL"
 PKG_SITE="http://www.alsa-project.org/"
-PKG_URL="ftp://ftp.alsa-project.org/pub/lib/alsa-lib-$PKG_VERSION.tar.bz2"
+PKG_URL="ftp://ftp.alsa-project.org/pub/lib/alsa-lib-${PKG_VERSION}.tar.bz2"
 PKG_DEPENDS_TARGET="toolchain"
 PKG_LONGDESC="ALSA (Advanced Linux Sound Architecture) is the next generation Linux Sound API."
 PKG_TOOLCHAIN="autotools"
@@ -19,7 +19,7 @@ else
   PKG_ALSA_DEBUG=--without-debug
 fi
 
-PKG_CONFIGURE_OPTS_TARGET="$PKG_ALSA_DEBUG \
+PKG_CONFIGURE_OPTS_TARGET="${PKG_ALSA_DEBUG} \
                            --disable-dependency-tracking \
                            --with-plugindir=/usr/lib/alsa \
                            --disable-python"
@@ -29,10 +29,10 @@ post_configure_target() {
 }
 
 post_makeinstall_target() {
-  rm -rf $INSTALL/usr/bin
+  rm -rf ${INSTALL}/usr/bin
 
-  mkdir -p $INSTALL/usr/config
-    cp -PR $PKG_DIR/config/modprobe.d $INSTALL/usr/config
+  mkdir -p ${INSTALL}/usr/config
+    cp -PR ${PKG_DIR}/config/modprobe.d ${INSTALL}/usr/config
 }
 
 post_install() {
diff --git a/packages/audio/alsa-topology-conf/package.mk b/packages/audio/alsa-topology-conf/package.mk
index d76b16405e..183ebe3202 100644
--- a/packages/audio/alsa-topology-conf/package.mk
+++ b/packages/audio/alsa-topology-conf/package.mk
@@ -6,7 +6,7 @@ PKG_VERSION="1.2.4"
 PKG_SHA256="55e0e6e42eca4cc7656c257af2440cdc65b83689dca49fc60ca0194db079ed07"
 PKG_LICENSE="BSD-3c"
 PKG_SITE="http://www.alsa-project.org/"
-PKG_URL="ftp://ftp.alsa-project.org/pub/lib/alsa-topology-conf-$PKG_VERSION.tar.bz2"
+PKG_URL="ftp://ftp.alsa-project.org/pub/lib/alsa-topology-conf-${PKG_VERSION}.tar.bz2"
 PKG_LONGDESC="ALSA topology configuration files"
 PKG_TOOLCHAIN="manual"
 
diff --git a/packages/audio/alsa-ucm-conf/package.mk b/packages/audio/alsa-ucm-conf/package.mk
index 43268c75a5..32769b3a7d 100644
--- a/packages/audio/alsa-ucm-conf/package.mk
+++ b/packages/audio/alsa-ucm-conf/package.mk
@@ -6,7 +6,7 @@ PKG_VERSION="1.2.4"
 PKG_SHA256="2c3b535c77dcb9aaf62a61f4f8324f1ab184162f105f7ec9ed1e37c742fcd340"
 PKG_LICENSE="BSD-3c"
 PKG_SITE="http://www.alsa-project.org/"
-PKG_URL="ftp://ftp.alsa-project.org/pub/lib/alsa-ucm-conf-$PKG_VERSION.tar.bz2"
+PKG_URL="ftp://ftp.alsa-project.org/pub/lib/alsa-ucm-conf-${PKG_VERSION}.tar.bz2"
 PKG_LONGDESC="ALSA Use Case Manager configuration (and topologies)"
 PKG_TOOLCHAIN="manual"
 
diff --git a/packages/audio/alsa-utils/package.mk b/packages/audio/alsa-utils/package.mk
index 5e51403f67..aba3c36810 100644
--- a/packages/audio/alsa-utils/package.mk
+++ b/packages/audio/alsa-utils/package.mk
@@ -7,7 +7,7 @@ PKG_VERSION="1.2.4"
 PKG_SHA256="98ffc2d599de0577d423a48fa5f20a992ca0b82d812ed1f2e58ade49ac6da426"
 PKG_LICENSE="GPL"
 PKG_SITE="http://www.alsa-project.org/"
-PKG_URL="ftp://ftp.alsa-project.org/pub/utils/alsa-utils-$PKG_VERSION.tar.bz2"
+PKG_URL="ftp://ftp.alsa-project.org/pub/utils/alsa-utils-${PKG_VERSION}.tar.bz2"
 PKG_DEPENDS_TARGET="toolchain alsa-lib ncurses systemd"
 PKG_LONGDESC="This package includes the utilities for ALSA, like alsamixer, aplay, arecord, alsactl, iecset and speaker-test."
 
@@ -21,20 +21,20 @@ PKG_CONFIGURE_OPTS_TARGET="--disable-alsaconf \
                            --disable-xmlto"
 
 post_makeinstall_target() {
-  rm -rf $INSTALL/lib $INSTALL/var
-  rm -rf $INSTALL/usr/share/alsa/speaker-test
-  rm -rf $INSTALL/usr/share/sounds
-  rm -rf $INSTALL/usr/lib/systemd/system
+  rm -rf ${INSTALL}/lib ${INSTALL}/var
+  rm -rf ${INSTALL}/usr/share/alsa/speaker-test
+  rm -rf ${INSTALL}/usr/share/sounds
+  rm -rf ${INSTALL}/usr/lib/systemd/system
 
 # remove default udev rule to restore mixer configs, we install our own.
 # so we avoid resetting our soundconfig
-  rm -rf $INSTALL/usr/lib/udev/rules.d/90-alsa-restore.rules
+  rm -rf ${INSTALL}/usr/lib/udev/rules.d/90-alsa-restore.rules
 
-  mkdir -p $INSTALL/.noinstall
+  mkdir -p ${INSTALL}/.noinstall
   for i in aconnect alsamixer amidi aplaymidi arecord arecordmidi aseqdump aseqnet iecset; do
-    mv $INSTALL/usr/bin/$i $INSTALL/.noinstall
+    mv ${INSTALL}/usr/bin/${i} ${INSTALL}/.noinstall
   done
 
-  mkdir -p $INSTALL/usr/lib/udev
-    cp $PKG_DIR/scripts/soundconfig $INSTALL/usr/lib/udev
+  mkdir -p ${INSTALL}/usr/lib/udev
+    cp ${PKG_DIR}/scripts/soundconfig ${INSTALL}/usr/lib/udev
 }
diff --git a/packages/audio/flac/package.mk b/packages/audio/flac/package.mk
index 54a843115c..551cdfdb19 100644
--- a/packages/audio/flac/package.mk
+++ b/packages/audio/flac/package.mk
@@ -7,7 +7,7 @@ PKG_VERSION="1.3.3"
 PKG_SHA256="213e82bd716c9de6db2f98bcadbc4c24c7e2efe8c75939a1a84e28539c4e1748"
 PKG_LICENSE="GPLv2"
 PKG_SITE="https://xiph.org/flac/"
-PKG_URL="http://downloads.xiph.org/releases/flac/$PKG_NAME-$PKG_VERSION.tar.xz"
+PKG_URL="http://downloads.xiph.org/releases/flac/${PKG_NAME}-${PKG_VERSION}.tar.xz"
 PKG_DEPENDS_TARGET="toolchain libogg"
 PKG_LONGDESC="An Free Lossless Audio Codec."
 PKG_TOOLCHAIN="autotools"
@@ -24,15 +24,15 @@ PKG_CONFIGURE_OPTS_TARGET="--enable-static \
                            --disable-cpplibs \
                            --disable-xmms-plugin \
                            --disable-oggtest \
-                           --with-ogg=$SYSROOT_PREFIX/usr \
+                           --with-ogg=${SYSROOT_PREFIX}/usr \
                            --with-gnu-ld"
 
 if target_has_feature sse; then
-  PKG_CONFIGURE_OPTS_TARGET="$PKG_CONFIGURE_OPTS_TARGET --enable-sse"
+  PKG_CONFIGURE_OPTS_TARGET+=" --enable-sse"
 else
-  PKG_CONFIGURE_OPTS_TARGET="$PKG_CONFIGURE_OPTS_TARGET --disable-sse"
+  PKG_CONFIGURE_OPTS_TARGET+=" --disable-sse"
 fi
 
 post_makeinstall_target() {
-  rm -rf $INSTALL/usr/bin
+  rm -rf ${INSTALL}/usr/bin
 }
diff --git a/packages/audio/fluidsynth/package.mk b/packages/audio/fluidsynth/package.mk
index 628c934934..d56a877982 100644
--- a/packages/audio/fluidsynth/package.mk
+++ b/packages/audio/fluidsynth/package.mk
@@ -7,7 +7,7 @@ PKG_VERSION="1.1.6"
 PKG_SHA256="d28b47dfbf7f8e426902ae7fa2981d821fbf84f41da9e1b85be933d2d748f601"
 PKG_LICENSE="GPL"
 PKG_SITE="http://fluidsynth.org/"
-PKG_URL="$SOURCEFORGE_SRC/project/fluidsynth/fluidsynth-$PKG_VERSION/$PKG_NAME-$PKG_VERSION.tar.bz2"
+PKG_URL="${SOURCEFORGE_SRC}/project/fluidsynth/fluidsynth-${PKG_VERSION}/${PKG_NAME}-${PKG_VERSION}.tar.bz2"
 PKG_DEPENDS_TARGET="toolchain glib"
 PKG_LONGDESC="FluidSynth renders midi music files as raw audio data, for playing or conversion."
 PKG_BUILD_FLAGS="+pic"
diff --git a/packages/audio/lame/package.mk b/packages/audio/lame/package.mk
index 192229c267..f15b34b017 100644
--- a/packages/audio/lame/package.mk
+++ b/packages/audio/lame/package.mk
@@ -6,7 +6,7 @@ PKG_VERSION="3.100"
 PKG_SHA256="ddfe36cab873794038ae2c1210557ad34857a4b6bdc515785d1da9e175b1da1e"
 PKG_LICENSE="LGPL"
 PKG_SITE="http://lame.sourceforge.net/"
-PKG_URL="$SOURCEFORGE_SRC/lame/lame/3.100/$PKG_NAME-$PKG_VERSION.tar.gz"
+PKG_URL="${SOURCEFORGE_SRC}/lame/lame/3.100/${PKG_NAME}-${PKG_VERSION}.tar.gz"
 PKG_DEPENDS_TARGET="toolchain"
 PKG_LONGDESC="A high quality MPEG Audio Layer III (MP3) encoder."
 PKG_BUILD_FLAGS="-parallel +pic"
diff --git a/packages/audio/libcdio/package.mk b/packages/audio/libcdio/package.mk
index 9a50b688b2..727fb59a09 100644
--- a/packages/audio/libcdio/package.mk
+++ b/packages/audio/libcdio/package.mk
@@ -7,7 +7,7 @@ PKG_VERSION="2.1.0"
 PKG_SHA256="8550e9589dbd594bfac93b81ecf129b1dc9d0d51e90f9696f1b2f9b2af32712b"
 PKG_LICENSE="GPLv3"
 PKG_SITE="https://www.gnu.org/software/libcdio/"
-PKG_URL="http://ftpmirror.gnu.org/libcdio/$PKG_NAME-$PKG_VERSION.tar.bz2"
+PKG_URL="http://ftpmirror.gnu.org/libcdio/${PKG_NAME}-${PKG_VERSION}.tar.bz2"
 PKG_DEPENDS_TARGET="toolchain"
 PKG_LONGDESC="A CD-ROM reading and control library."
 PKG_BUILD_FLAGS="+pic"
@@ -32,5 +32,5 @@ PKG_CONFIGURE_OPTS_TARGET="--enable-cxx \
                            --with-gnu-ld"
 
 post_makeinstall_target() {
-  rm -rf $INSTALL/usr/bin
+  rm -rf ${INSTALL}/usr/bin
 }
diff --git a/packages/audio/libmodplug/package.mk b/packages/audio/libmodplug/package.mk
index ee45fd2725..26651b2503 100644
--- a/packages/audio/libmodplug/package.mk
+++ b/packages/audio/libmodplug/package.mk
@@ -7,7 +7,7 @@ PKG_VERSION="0.8.9.0"
 PKG_SHA256="457ca5a6c179656d66c01505c0d95fafaead4329b9dbaa0f997d00a3508ad9de"
 PKG_LICENSE="GPL"
 PKG_SITE="http://modplug-xmms.sourceforge.net/"
-PKG_URL="$SOURCEFORGE_SRC/modplug-xmms/libmodplug/$PKG_VERSION/$PKG_NAME-$PKG_VERSION.tar.gz"
+PKG_URL="${SOURCEFORGE_SRC}/modplug-xmms/libmodplug/${PKG_VERSION}/${PKG_NAME}-${PKG_VERSION}.tar.gz"
 PKG_DEPENDS_TARGET="toolchain"
 PKG_LONGDESC="libmodplug renders mod music files as raw audio data, for playing or conversion."
 PKG_BUILD_FLAGS="+pic"
diff --git a/packages/audio/libogg/package.mk b/packages/audio/libogg/package.mk
index b99029e84f..e0e1cf4dd1 100644
--- a/packages/audio/libogg/package.mk
+++ b/packages/audio/libogg/package.mk
@@ -7,7 +7,7 @@ PKG_VERSION="1.3.4"
 PKG_SHA256="c163bc12bc300c401b6aa35907ac682671ea376f13ae0969a220f7ddf71893fe"
 PKG_LICENSE="BSD"
 PKG_SITE="https://www.xiph.org/ogg/"
-PKG_URL="http://downloads.xiph.org/releases/ogg/libogg-$PKG_VERSION.tar.xz"
+PKG_URL="http://downloads.xiph.org/releases/ogg/libogg-${PKG_VERSION}.tar.xz"
 PKG_DEPENDS_TARGET="toolchain"
 PKG_LONGDESC="Libogg contains necessary functionality to create, decode, and work with Ogg bitstreams."
 PKG_BUILD_FLAGS="+pic"
diff --git a/packages/audio/libsamplerate/package.mk b/packages/audio/libsamplerate/package.mk
index 75194dc676..092c7c1bd4 100644
--- a/packages/audio/libsamplerate/package.mk
+++ b/packages/audio/libsamplerate/package.mk
@@ -7,7 +7,7 @@ PKG_VERSION="0.1.9"
 PKG_SHA256="0a7eb168e2f21353fb6d84da152e4512126f7dc48ccb0be80578c565413444c1"
 PKG_LICENSE="GPL"
 PKG_SITE="http://www.mega-nerd.com/SRC/"
-PKG_URL="http://www.mega-nerd.com/SRC/$PKG_NAME-$PKG_VERSION.tar.gz"
+PKG_URL="http://www.mega-nerd.com/SRC/${PKG_NAME}-${PKG_VERSION}.tar.gz"
 PKG_DEPENDS_TARGET="toolchain"
 PKG_LONGDESC="A Sample Rate Converter for audio."
 
@@ -19,5 +19,5 @@ PKG_CONFIGURE_OPTS_TARGET="--disable-shared \
                            --disable-sndfile"
 
 post_makeinstall_target() {
-  rm -rf $INSTALL/usr/bin
+  rm -rf ${INSTALL}/usr/bin
 }
diff --git a/packages/audio/libsndfile/package.mk b/packages/audio/libsndfile/package.mk
index f213523382..2843bc2108 100644
--- a/packages/audio/libsndfile/package.mk
+++ b/packages/audio/libsndfile/package.mk
@@ -6,7 +6,7 @@ PKG_VERSION="1.0.28"
 PKG_SHA256="1ff33929f042fa333aed1e8923aa628c3ee9e1eb85512686c55092d1e5a9dfa9"
 PKG_LICENSE="LGPL"
 PKG_SITE="http://www.mega-nerd.com/libsndfile/"
-PKG_URL="http://www.mega-nerd.com/$PKG_NAME/files/$PKG_NAME-$PKG_VERSION.tar.gz"
+PKG_URL="http://www.mega-nerd.com/${PKG_NAME}/files/${PKG_NAME}-${PKG_VERSION}.tar.gz"
 PKG_DEPENDS_TARGET="toolchain alsa-lib"
 PKG_LONGDESC="A library for accessing various audio file formats."
 PKG_TOOLCHAIN="configure"
@@ -24,5 +24,5 @@ PKG_CONFIGURE_OPTS_TARGET="--enable-static --disable-shared \
                            --with-pic"
 
 post_makeinstall_target() {
-  rm -rf $INSTALL/usr/bin
+  rm -rf ${INSTALL}/usr/bin
 }
diff --git a/packages/audio/libvorbis/package.mk b/packages/audio/libvorbis/package.mk
index 1863c1df02..2b72481931 100644
--- a/packages/audio/libvorbis/package.mk
+++ b/packages/audio/libvorbis/package.mk
@@ -7,7 +7,7 @@ PKG_VERSION="1.3.7"
 PKG_SHA256="b33cc4934322bcbf6efcbacf49e3ca01aadbea4114ec9589d1b1e9d20f72954b"
 PKG_LICENSE="BSD"
 PKG_SITE="http://www.vorbis.com/"
-PKG_URL="http://downloads.xiph.org/releases/vorbis/libvorbis-$PKG_VERSION.tar.xz"
+PKG_URL="http://downloads.xiph.org/releases/vorbis/libvorbis-${PKG_VERSION}.tar.xz"
 PKG_DEPENDS_TARGET="toolchain libogg"
 PKG_LONGDESC="Lossless audio compression tools using the ogg-vorbis algorithms."
 PKG_TOOLCHAIN="autotools"
@@ -15,7 +15,7 @@ PKG_BUILD_FLAGS="+pic"
 
 PKG_CONFIGURE_OPTS_TARGET="--enable-static \
                            --disable-shared \
-                           --with-ogg=$SYSROOT_PREFIX/usr \
+                           --with-ogg=${SYSROOT_PREFIX}/usr \
                            --disable-docs \
                            --disable-examples \
                            --disable-oggtest"
diff --git a/packages/audio/openal-soft/package.mk b/packages/audio/openal-soft/package.mk
index 1dfc804849..0f73a0549f 100644
--- a/packages/audio/openal-soft/package.mk
+++ b/packages/audio/openal-soft/package.mk
@@ -6,7 +6,7 @@ PKG_VERSION="1.21.0"
 PKG_SHA256="cd3650530866f3906058225f4bfbe0052be19e0a29dcc6df185a460f9948feec"
 PKG_LICENSE="GPL"
 PKG_SITE="http://www.openal.org/"
-PKG_URL="https://github.com/kcat/openal-soft/archive/$PKG_NAME-$PKG_VERSION.tar.gz"
+PKG_URL="https://github.com/kcat/openal-soft/archive/${PKG_NAME}-${PKG_VERSION}.tar.gz"
 PKG_DEPENDS_HOST="toolchain:host"
 PKG_DEPENDS_TARGET="toolchain openal-soft:host alsa-lib"
 PKG_LONGDESC="OpenAL the Open Audio Library"
@@ -18,7 +18,7 @@ configure_package() {
                        -DALSOFT_TESTS=off \
                        -DALSOFT_UTILS=off"
 
-  PKG_CMAKE_OPTS_TARGET="-DALSOFT_NATIVE_TOOLS_PATH=$PKG_BUILD/.$HOST_NAME/native-tools/ \
+  PKG_CMAKE_OPTS_TARGET="-DALSOFT_NATIVE_TOOLS_PATH=${PKG_BUILD}/.${HOST_NAME}/native-tools/ \
                          -DALSOFT_BACKEND_OSS=off \
                          -DALSOFT_BACKEND_WAVE=off \
                          -DALSOFT_BACKEND_PULSEAUDIO=off \
diff --git a/packages/audio/pulseaudio/package.mk b/packages/audio/pulseaudio/package.mk
index d1aa1e45a0..7b6dea28cf 100644
--- a/packages/audio/pulseaudio/package.mk
+++ b/packages/audio/pulseaudio/package.mk
@@ -7,20 +7,20 @@ PKG_VERSION="14.0"
 PKG_SHA256="a834775d9382b055504e5ee7625dc50768daac29329531deb6597bf05e06c261"
 PKG_LICENSE="GPL"
 PKG_SITE="http://pulseaudio.org/"
-PKG_URL="http://www.freedesktop.org/software/pulseaudio/releases/$PKG_NAME-$PKG_VERSION.tar.xz"
+PKG_URL="http://www.freedesktop.org/software/pulseaudio/releases/${PKG_NAME}-${PKG_VERSION}.tar.xz"
 PKG_DEPENDS_TARGET="toolchain alsa-lib dbus libcap libsndfile libtool openssl soxr speexdsp systemd glib:host glib"
 PKG_LONGDESC="PulseAudio is a sound system for POSIX OSes, meaning that it is a proxy for your sound applications."
 PKG_TOOLCHAIN="meson"
 
-if [ "$BLUETOOTH_SUPPORT" = "yes" ]; then
-  PKG_DEPENDS_TARGET="$PKG_DEPENDS_TARGET sbc"
+if [ "${BLUETOOTH_SUPPORT}" = "yes" ]; then
+  PKG_DEPENDS_TARGET+=" sbc"
   PKG_PULSEAUDIO_BLUETOOTH="-Dbluez5=true"
 else
   PKG_PULSEAUDIO_BLUETOOTH="-Dbluez5=false"
 fi
 
-if [ "$AVAHI_DAEMON" = "yes" ]; then
-  PKG_DEPENDS_TARGET="$PKG_DEPENDS_TARGET avahi"
+if [ "${AVAHI_DAEMON}" = "yes" ]; then
+  PKG_DEPENDS_TARGET+=" avahi"
   PKG_PULSEAUDIO_AVAHI="-Davahi=enabled"
 else
   PKG_PULSEAUDIO_AVAHI="-Davahi=disabled"
@@ -41,8 +41,8 @@ PKG_MESON_OPTS_TARGET="-Dgcov=false \
                        -Dudevrulesdir=/usr/lib/udev/rules.d \
                        -Dalsa=enabled \
                        -Dasyncns=disabled \
-                       $PKG_PULSEAUDIO_AVAHI \
-                       $PKG_PULSEAUDIO_BLUETOOTH \
+                       ${PKG_PULSEAUDIO_AVAHI} \
+                       ${PKG_PULSEAUDIO_BLUETOOTH} \
                        -Dbluez5-native-headset=false \
                        -Dbluez5-ofono-headset=false \
                        -Ddbus=enabled \
@@ -67,25 +67,25 @@ PKG_MESON_OPTS_TARGET="-Dgcov=false \
 
 pre_configure_target() {
   sed -e 's|; remixing-use-all-sink-channels = yes|; remixing-use-all-sink-channels = no|' \
-      -i $PKG_BUILD/src/daemon/daemon.conf.in
+      -i ${PKG_BUILD}/src/daemon/daemon.conf.in
 }
 
 post_makeinstall_target() {
-  safe_remove $INSTALL/usr/include
-  safe_remove $INSTALL/usr/lib/cmake
-  safe_remove $INSTALL/usr/lib/pkgconfig
-  safe_remove $INSTALL/usr/lib/systemd
-  safe_remove $INSTALL/usr/share/vala
-  safe_remove $INSTALL/usr/share/zsh
-  safe_remove $INSTALL/usr/share/bash-completion
+  safe_remove ${INSTALL}/usr/include
+  safe_remove ${INSTALL}/usr/lib/cmake
+  safe_remove ${INSTALL}/usr/lib/pkgconfig
+  safe_remove ${INSTALL}/usr/lib/systemd
+  safe_remove ${INSTALL}/usr/share/vala
+  safe_remove ${INSTALL}/usr/share/zsh
+  safe_remove ${INSTALL}/usr/share/bash-completion
 
-  cp $PKG_DIR/config/system.pa $INSTALL/etc/pulse/
-  cp $PKG_DIR/config/pulseaudio-system.conf $INSTALL/etc/dbus-1/system.d/
+  cp ${PKG_DIR}/config/system.pa ${INSTALL}/etc/pulse/
+  cp ${PKG_DIR}/config/pulseaudio-system.conf ${INSTALL}/etc/dbus-1/system.d/
 
-  mkdir -p $INSTALL/usr/config
-    cp -PR $PKG_DIR/config/pulse-daemon.conf.d $INSTALL/usr/config
+  mkdir -p ${INSTALL}/usr/config
+    cp -PR ${PKG_DIR}/config/pulse-daemon.conf.d ${INSTALL}/usr/config
 
-  ln -sf /storage/.config/pulse-daemon.conf.d $INSTALL/etc/pulse/daemon.conf.d
+  ln -sf /storage/.config/pulse-daemon.conf.d ${INSTALL}/etc/pulse/daemon.conf.d
 }
 
 post_install() {
diff --git a/packages/audio/rpi-cirrus-config/package.mk b/packages/audio/rpi-cirrus-config/package.mk
index d775489fdb..f0f6eccae6 100644
--- a/packages/audio/rpi-cirrus-config/package.mk
+++ b/packages/audio/rpi-cirrus-config/package.mk
@@ -6,21 +6,21 @@ PKG_VERSION="0.0.2"
 PKG_SHA256="cc11c47f1f2b6d5e72dcdea828ba57e0dcaf74161f675a4a9f395054f5d82d31"
 PKG_LICENSE="GPL"
 PKG_SITE="https://github.com/HiassofT/rpi-cirrus-config"
-PKG_URL="https://github.com/HiassofT/rpi-cirrus-config/archive/$PKG_VERSION.tar.gz"
+PKG_URL="https://github.com/HiassofT/rpi-cirrus-config/archive/${PKG_VERSION}.tar.gz"
 PKG_DEPENDS_TARGET="alsa-utils"
 PKG_LONGDESC="Config scripts for the Wolfson/Cirrus Logic audio card"
 PKG_TOOLCHAIN="manual"
 
 makeinstall_target() {
-  mkdir -p $INSTALL/usr/lib/udev
-  install -m 0755 $PKG_DIR/scripts/rpi-cirrus-config $INSTALL/usr/lib/udev/rpi-cirrus-config
+  mkdir -p ${INSTALL}/usr/lib/udev
+  install -m 0755 ${PKG_DIR}/scripts/rpi-cirrus-config ${INSTALL}/usr/lib/udev/rpi-cirrus-config
 
-  mkdir -p $INSTALL/usr/share/alsa/cards
-  cp alsa/RPiCirrus.conf $INSTALL/usr/share/alsa/cards
+  mkdir -p ${INSTALL}/usr/share/alsa/cards
+  cp alsa/RPiCirrus.conf ${INSTALL}/usr/share/alsa/cards
 
-  mkdir -p $INSTALL/usr/lib/alsa
-  cp mixer-scripts/rpi-cirrus-functions.sh $INSTALL/usr/lib/alsa
+  mkdir -p ${INSTALL}/usr/lib/alsa
+  cp mixer-scripts/rpi-cirrus-functions.sh ${INSTALL}/usr/lib/alsa
 
-  mkdir -p $INSTALL/usr/config
-  cp -PR $PKG_DIR/config/* $INSTALL/usr/config
+  mkdir -p ${INSTALL}/usr/config
+  cp -PR ${PKG_DIR}/config/* ${INSTALL}/usr/config
 }
diff --git a/packages/audio/sbc/package.mk b/packages/audio/sbc/package.mk
index 769e4d2709..1ce5f02fb1 100644
--- a/packages/audio/sbc/package.mk
+++ b/packages/audio/sbc/package.mk
@@ -7,7 +7,7 @@ PKG_VERSION="1.5"
 PKG_SHA256="51d4e385237e9d4780c7b20e660e30fb6a7a6d75ca069f1ed630fa6105232aba"
 PKG_LICENSE="GPL"
 PKG_SITE="http://www.bluez.org/"
-PKG_URL="http://www.kernel.org/pub/linux/bluetooth/sbc-$PKG_VERSION.tar.gz"
+PKG_URL="http://www.kernel.org/pub/linux/bluetooth/sbc-${PKG_VERSION}.tar.gz"
 PKG_DEPENDS_TARGET="toolchain"
 PKG_LONGDESC="standalone SBC library"
 PKG_BUILD_FLAGS="+pic"
diff --git a/packages/audio/sidplay-libs/package.mk b/packages/audio/sidplay-libs/package.mk
index f958ed1c8c..7f98382ec6 100644
--- a/packages/audio/sidplay-libs/package.mk
+++ b/packages/audio/sidplay-libs/package.mk
@@ -6,7 +6,7 @@ PKG_VERSION="2.1.1"
 PKG_SHA256="e9a24ada48215a46d2c232a70c5601bc9505e997f120e8f2ba3713e09e28d1f9"
 PKG_LICENSE="GPL"
 PKG_SITE="http://sidplay2.sourceforge.net/"
-PKG_URL="http://mirrors.xbmc.org/build-deps/sources/$PKG_NAME-$PKG_VERSION.tar.gz"
+PKG_URL="http://mirrors.xbmc.org/build-deps/sources/${PKG_NAME}-${PKG_VERSION}.tar.gz"
 PKG_DEPENDS_TARGET="toolchain"
 PKG_LONGDESC="sidplay-libs"
 PKG_BUILD_FLAGS="+pic"
@@ -15,8 +15,8 @@ PKG_CONFIGURE_OPTS_TARGET="--disable-shared --enable-static"
 
 pre_configure_target() {
   # fails to build in subdirs
-  cd $PKG_BUILD
-  rm -rf .$TARGET_NAME
+  cd ${PKG_BUILD}
+  rm -rf .${TARGET_NAME}
 
-  export CXXFLAGS="$CXXFLAGS -Wno-narrowing"
+  export CXXFLAGS="${CXXFLAGS} -Wno-narrowing"
 }
diff --git a/packages/audio/soxr/package.mk b/packages/audio/soxr/package.mk
index 677ec5c675..847b5df52c 100644
--- a/packages/audio/soxr/package.mk
+++ b/packages/audio/soxr/package.mk
@@ -7,7 +7,7 @@ PKG_VERSION="0.1.3"
 PKG_SHA256="b111c15fdc8c029989330ff559184198c161100a59312f5dc19ddeb9b5a15889"
 PKG_LICENSE="LGPL"
 PKG_SITE="https://sourceforge.net/projects/soxr/"
-PKG_URL="$SOURCEFORGE_SRC/soxr/soxr-$PKG_VERSION-Source.tar.xz"
+PKG_URL="${SOURCEFORGE_SRC}/soxr/soxr-${PKG_VERSION}-Source.tar.xz"
 PKG_DEPENDS_TARGET="toolchain cmake:host"
 PKG_LONGDESC="The SoX Resampler library performs one-dimensional sample-rate conversion. It may be used to resample PCM-encoded audio."
 PKG_BUILD_FLAGS="+pic"
@@ -17,7 +17,7 @@ PKG_CMAKE_OPTS_TARGET="-DBUILD_EXAMPLES=OFF \
                        -DBUILD_TESTS=OFF \
                        -DWITH_AVFFT=OFF"
 
-if [ "$TARGET_ARCH" = "arm" ]; then
+if [ "${TARGET_ARCH}" = "arm" ]; then
   if target_has_feature neon; then
     PKG_CMAKE_OPTS_TARGET+=" -DWITH_CR32=OFF"
   else
diff --git a/packages/audio/speex/package.mk b/packages/audio/speex/package.mk
index c821495368..22ac83736d 100644
--- a/packages/audio/speex/package.mk
+++ b/packages/audio/speex/package.mk
@@ -7,6 +7,6 @@ PKG_VERSION="1.2.0"
 PKG_SHA256="eaae8af0ac742dc7d542c9439ac72f1f385ce838392dc849cae4536af9210094"
 PKG_LICENSE="BSD"
 PKG_SITE="https://speex.org"
-PKG_URL="http://downloads.us.xiph.org/releases/speex/speex-$PKG_VERSION.tar.gz"
+PKG_URL="http://downloads.us.xiph.org/releases/speex/speex-${PKG_VERSION}.tar.gz"
 PKG_DEPENDS_TARGET="toolchain"
 PKG_LONGDESC="An Open Source Software patent-free audio compression format designed for speech."
diff --git a/packages/audio/speexdsp/package.mk b/packages/audio/speexdsp/package.mk
index 288ba6bb73..18accd9a2c 100644
--- a/packages/audio/speexdsp/package.mk
+++ b/packages/audio/speexdsp/package.mk
@@ -6,6 +6,6 @@ PKG_VERSION="1.2.0"
 PKG_SHA256="682042fc6f9bee6294ec453f470dadc26c6ff29b9c9e9ad2ffc1f4312fd64771"
 PKG_LICENSE="BSD"
 PKG_SITE="https://speex.org"
-PKG_URL="http://downloads.us.xiph.org/releases/speex/speexdsp-$PKG_VERSION.tar.gz"
+PKG_URL="http://downloads.us.xiph.org/releases/speex/speexdsp-${PKG_VERSION}.tar.gz"
 PKG_DEPENDS_TARGET="toolchain"
 PKG_LONGDESC="Speex audio processing library"
diff --git a/packages/audio/taglib/package.mk b/packages/audio/taglib/package.mk
index 3f695bcada..244a52fd82 100644
--- a/packages/audio/taglib/package.mk
+++ b/packages/audio/taglib/package.mk
@@ -6,7 +6,7 @@ PKG_VERSION="1.11.1"
 PKG_SHA256="b6d1a5a610aae6ff39d93de5efd0fdc787aa9e9dc1e7026fa4c961b26563526b"
 PKG_LICENSE="LGPL"
 PKG_SITE="http://taglib.github.com/"
-PKG_URL="http://taglib.github.io/releases/$PKG_NAME-$PKG_VERSION.tar.gz"
+PKG_URL="http://taglib.github.io/releases/${PKG_NAME}-${PKG_VERSION}.tar.gz"
 PKG_DEPENDS_TARGET="toolchain cmake:host zlib"
 PKG_LONGDESC="TagLib is a library for reading and editing the meta-data of several popular audio formats."
 
@@ -15,11 +15,11 @@ PKG_CMAKE_OPTS_TARGET="-DBUILD_SHARED_LIBS=OFF \
                        -DWITH_ASF=ON"
 
 post_makeinstall_target() {
-  rm -rf $INSTALL/usr/bin
+  rm -rf ${INSTALL}/usr/bin
   # pkgconf hack
-  sed -e "s:\(['=\" ]\)/usr:\\1$SYSROOT_PREFIX/usr:g" -i $SYSROOT_PREFIX/usr/bin/taglib-config
-  sed -e "s:\([':\" ]\)-I/usr:\\1-I$SYSROOT_PREFIX/usr:g" -i $SYSROOT_PREFIX/usr/lib/pkgconfig/taglib.pc
-  sed -e "s:\([':\" ]\)-L/usr:\\1-L$SYSROOT_PREFIX/usr:g" -i $SYSROOT_PREFIX/usr/lib/pkgconfig/taglib.pc
-  sed -e "s:\([':\" ]\)-I/usr:\\1-I$SYSROOT_PREFIX/usr:g" -i $SYSROOT_PREFIX/usr/lib/pkgconfig/taglib_c.pc
-  sed -e "s:\([':\" ]\)-L/usr:\\1-L$SYSROOT_PREFIX/usr:g" -i $SYSROOT_PREFIX/usr/lib/pkgconfig/taglib_c.pc
+  sed -e "s:\(['=\" ]\)/usr:\\1${SYSROOT_PREFIX}/usr:g" -i ${SYSROOT_PREFIX}/usr/bin/taglib-config
+  sed -e "s:\([':\" ]\)-I/usr:\\1-I${SYSROOT_PREFIX}/usr:g" -i ${SYSROOT_PREFIX}/usr/lib/pkgconfig/taglib.pc
+  sed -e "s:\([':\" ]\)-L/usr:\\1-L${SYSROOT_PREFIX}/usr:g" -i ${SYSROOT_PREFIX}/usr/lib/pkgconfig/taglib.pc
+  sed -e "s:\([':\" ]\)-I/usr:\\1-I${SYSROOT_PREFIX}/usr:g" -i ${SYSROOT_PREFIX}/usr/lib/pkgconfig/taglib_c.pc
+  sed -e "s:\([':\" ]\)-L/usr:\\1-L${SYSROOT_PREFIX}/usr:g" -i ${SYSROOT_PREFIX}/usr/lib/pkgconfig/taglib_c.pc
 }