diff --git a/packages/compress/bzip2/package.mk b/packages/compress/bzip2/package.mk
index 4767dec9ab..ac9ac5d3ff 100644
--- a/packages/compress/bzip2/package.mk
+++ b/packages/compress/bzip2/package.mk
@@ -14,31 +14,31 @@ PKG_LONGDESC="A high-quality bzip2 data compressor."
 PKG_BUILD_FLAGS="+pic +pic:host"
 
 pre_build_host() {
-  mkdir -p $PKG_BUILD/.$HOST_NAME
-  cp -r $PKG_BUILD/* $PKG_BUILD/.$HOST_NAME
+  mkdir -p ${PKG_BUILD}/.${HOST_NAME}
+  cp -r ${PKG_BUILD}/* ${PKG_BUILD}/.${HOST_NAME}
 }
 
 make_host() {
-  cd $PKG_BUILD/.$HOST_NAME
-  make -f Makefile-libbz2_so CC=$HOST_CC CFLAGS="$CFLAGS"
+  cd ${PKG_BUILD}/.${HOST_NAME}
+  make -f Makefile-libbz2_so CC=${HOST_CC} CFLAGS="${CFLAGS}"
 }
 
 makeinstall_host() {
-  make install PREFIX=$TOOLCHAIN
+  make install PREFIX=${TOOLCHAIN}
 }
 
 pre_build_target() {
-  mkdir -p $PKG_BUILD/.$TARGET_NAME
-  cp -r $PKG_BUILD/* $PKG_BUILD/.$TARGET_NAME
+  mkdir -p ${PKG_BUILD}/.${TARGET_NAME}
+  cp -r ${PKG_BUILD}/* ${PKG_BUILD}/.${TARGET_NAME}
 }
 
 pre_make_target() {
-  cd $PKG_BUILD/.$TARGET_NAME
-  sed -e "s,ln -s (lib.*),ln -snf \$$1; ln -snf libbz2.so.$PKG_VERSION libbz2.so,g" -i Makefile-libbz2_so
+  cd ${PKG_BUILD}/.${TARGET_NAME}
+  sed -e "s,ln -s (lib.*),ln -snf \$${1}; ln -snf libbz2.so.${PKG_VERSION} libbz2.so,g" -i Makefile-libbz2_so
 }
 
 make_target() {
-  make -f Makefile-libbz2_so CC=$CC CFLAGS="$CFLAGS"
+  make -f Makefile-libbz2_so CC=${CC} CFLAGS="${CFLAGS}"
 }
 
 post_make_target() {
@@ -46,11 +46,11 @@ post_make_target() {
 }
 
 makeinstall_target() {
-  mkdir -p $SYSROOT_PREFIX/usr/include
-    cp bzlib.h $SYSROOT_PREFIX/usr/include
-  mkdir -p $SYSROOT_PREFIX/usr/lib
-    cp -P libbz2.so* $SYSROOT_PREFIX/usr/lib
+  mkdir -p ${SYSROOT_PREFIX}/usr/include
+    cp bzlib.h ${SYSROOT_PREFIX}/usr/include
+  mkdir -p ${SYSROOT_PREFIX}/usr/lib
+    cp -P libbz2.so* ${SYSROOT_PREFIX}/usr/lib
 
-  mkdir -p $INSTALL/usr/lib
-    cp -P libbz2.so* $INSTALL/usr/lib
+  mkdir -p ${INSTALL}/usr/lib
+    cp -P libbz2.so* ${INSTALL}/usr/lib
 }
diff --git a/packages/compress/libarchive/package.mk b/packages/compress/libarchive/package.mk
index bc76394443..31e05445f6 100644
--- a/packages/compress/libarchive/package.mk
+++ b/packages/compress/libarchive/package.mk
@@ -6,7 +6,7 @@ PKG_VERSION="3.5.1"
 PKG_SHA256="0e17d3a8d0b206018693b27f08029b598f6ef03600c2b5d10c94ce58692e299b"
 PKG_LICENSE="GPL"
 PKG_SITE="https://www.libarchive.org"
-PKG_URL="https://www.libarchive.org/downloads/$PKG_NAME-$PKG_VERSION.tar.xz"
+PKG_URL="https://www.libarchive.org/downloads/${PKG_NAME}-${PKG_VERSION}.tar.xz"
 PKG_DEPENDS_HOST="toolchain:host"
 PKG_DEPENDS_TARGET="toolchain"
 PKG_SHORTDESC="A multi-format archive and compression library."
@@ -21,8 +21,8 @@ PKG_CMAKE_OPTS_TARGET="-DCMAKE_POSITION_INDEPENDENT_CODE=1 \
                        -DENABLE_WERROR=0"
 
 post_makeinstall_target() {
-  rm -rf $INSTALL
+  rm -rf ${INSTALL}
 
   # delete the shared library as we only want static
-  rm $SYSROOT_PREFIX/usr/lib/libarchive.so*
+  rm ${SYSROOT_PREFIX}/usr/lib/libarchive.so*
 }
diff --git a/packages/compress/lz4/package.mk b/packages/compress/lz4/package.mk
index c1729c88dc..bcc4b79aa2 100644
--- a/packages/compress/lz4/package.mk
+++ b/packages/compress/lz4/package.mk
@@ -6,18 +6,18 @@ PKG_VERSION="1.9.3"
 PKG_SHA256="030644df4611007ff7dc962d981f390361e6c97a34e5cbc393ddfbe019ffe2c1"
 PKG_LICENSE="GPL"
 PKG_SITE="https://github.com/lz4/lz4"
-PKG_URL="https://github.com/lz4/lz4/archive/v$PKG_VERSION.tar.gz"
+PKG_URL="https://github.com/lz4/lz4/archive/v${PKG_VERSION}.tar.gz"
 PKG_DEPENDS_HOST="toolchain:host"
 PKG_DEPENDS_TARGET="toolchain"
 PKG_LONGDESC="lz4 data compressor/decompressor"
 PKG_TOOLCHAIN="cmake"
 
 configure_package() {
-  PKG_CMAKE_SCRIPT="$PKG_BUILD/build/cmake/CMakeLists.txt"
+  PKG_CMAKE_SCRIPT="${PKG_BUILD}/build/cmake/CMakeLists.txt"
 
   PKG_CMAKE_OPTS_TARGET="-DBUILD_SHARED_LIBS=0 -DCMAKE_POSITION_INDEPENDENT_CODE=0"
 }
 
 post_makeinstall_target() {
-  rm -rf $INSTALL
+  rm -rf ${INSTALL}
 }
diff --git a/packages/compress/lzo/package.mk b/packages/compress/lzo/package.mk
index 87f52fe1a8..dc0ed3bb7f 100644
--- a/packages/compress/lzo/package.mk
+++ b/packages/compress/lzo/package.mk
@@ -6,7 +6,7 @@ PKG_VERSION="2.10"
 PKG_SHA256="c0f892943208266f9b6543b3ae308fab6284c5c90e627931446fb49b4221a072"
 PKG_LICENSE="GPL"
 PKG_SITE="http://www.oberhumer.com/opensource/lzo"
-PKG_URL="http://www.oberhumer.com/opensource/lzo/download/$PKG_NAME-$PKG_VERSION.tar.gz"
+PKG_URL="http://www.oberhumer.com/opensource/lzo/download/${PKG_NAME}-${PKG_VERSION}.tar.gz"
 PKG_DEPENDS_HOST="toolchain:host"
 PKG_DEPENDS_TARGET="toolchain"
 PKG_LONGDESC="A data compression library which is suitable for data de-/compression."
@@ -16,5 +16,5 @@ PKG_CMAKE_OPTS_HOST="-DENABLE_SHARED=OFF -DENABLE_STATIC=ON"
 PKG_CMAKE_OPTS_TARGET="-DENABLE_SHARED=OFF -DENABLE_STATIC=ON"
 
 post_makeinstall_target() {
-  rm -rf $INSTALL/usr/libexec
+  rm -rf ${INSTALL}/usr/libexec
 }
diff --git a/packages/compress/p7zip/package.mk b/packages/compress/p7zip/package.mk
index 2a78613249..3a539ceb5e 100644
--- a/packages/compress/p7zip/package.mk
+++ b/packages/compress/p7zip/package.mk
@@ -13,34 +13,34 @@ PKG_LONGDESC="p7zip is a port of 7za.exe for POSIX systems like Unix."
 PKG_TOOLCHAIN="manual"
 
 pre_build_host() {
-  rm -fr $PKG_BUILD/.$HOST_NAME
-  mkdir -p $PKG_BUILD/.$HOST_NAME
-  cp -RP $PKG_BUILD/* $PKG_BUILD/.$HOST_NAME
+  rm -fr ${PKG_BUILD}/.${HOST_NAME}
+  mkdir -p ${PKG_BUILD}/.${HOST_NAME}
+  cp -RP ${PKG_BUILD}/* ${PKG_BUILD}/.${HOST_NAME}
 }
 
 make_host() {
-  make CXX=$CXX CC=$CC -C $PKG_BUILD/.$HOST_NAME 7za
+  make CXX=${CXX} CC=${CC} -C ${PKG_BUILD}/.${HOST_NAME} 7za
 }
 
 makeinstall_host() {
-  mkdir -p $TOOLCHAIN/bin
-    cp $PKG_BUILD/.$HOST_NAME/bin/7za $TOOLCHAIN/bin
+  mkdir -p ${TOOLCHAIN}/bin
+    cp ${PKG_BUILD}/.${HOST_NAME}/bin/7za ${TOOLCHAIN}/bin
 }
 
 pre_build_target() {
-  rm -fr $PKG_BUILD/.$TARGET_NAME
-  mkdir -p $PKG_BUILD/.$TARGET_NAME
-  cp -RP $PKG_BUILD/* $PKG_BUILD/.$TARGET_NAME
+  rm -fr ${PKG_BUILD}/.${TARGET_NAME}
+  mkdir -p ${PKG_BUILD}/.${TARGET_NAME}
+  cp -RP ${PKG_BUILD}/* ${PKG_BUILD}/.${TARGET_NAME}
 }
 
 make_target() {
-  make CXX=$CXX CC=$CC -C $PKG_BUILD/.$TARGET_NAME 7z 7za
+  make CXX=${CXX} CC=${CC} -C ${PKG_BUILD}/.${TARGET_NAME} 7z 7za
 }
 
 makeinstall_target() {
-  mkdir -p $INSTALL/usr/bin
-    cp -p $PKG_BUILD/.$TARGET_NAME/bin/7z.so $INSTALL/usr/bin
-    cp -pr $PKG_BUILD/.$TARGET_NAME/bin/Codecs $INSTALL/usr/bin
-    cp -p $PKG_BUILD/.$TARGET_NAME/bin/7z $INSTALL/usr/bin
-    cp -p $PKG_BUILD/.$TARGET_NAME/bin/7za $INSTALL/usr/bin
+  mkdir -p ${INSTALL}/usr/bin
+    cp -p ${PKG_BUILD}/.${TARGET_NAME}/bin/7z.so ${INSTALL}/usr/bin
+    cp -pr ${PKG_BUILD}/.${TARGET_NAME}/bin/Codecs ${INSTALL}/usr/bin
+    cp -p ${PKG_BUILD}/.${TARGET_NAME}/bin/7z ${INSTALL}/usr/bin
+    cp -p ${PKG_BUILD}/.${TARGET_NAME}/bin/7za ${INSTALL}/usr/bin
 }
diff --git a/packages/compress/pigz/package.mk b/packages/compress/pigz/package.mk
index 4196cda0d7..738e3fbb17 100644
--- a/packages/compress/pigz/package.mk
+++ b/packages/compress/pigz/package.mk
@@ -20,6 +20,6 @@ make_host() {
 }
 
 makeinstall_host() {
-  mkdir -p $TOOLCHAIN/bin
+  mkdir -p ${TOOLCHAIN}/bin
     cp pigz ${TOOLCHAIN}/bin
 }
diff --git a/packages/compress/xz/package.mk b/packages/compress/xz/package.mk
index a1f7dff346..41b48c1acd 100644
--- a/packages/compress/xz/package.mk
+++ b/packages/compress/xz/package.mk
@@ -7,7 +7,7 @@ PKG_VERSION="5.2.5"
 PKG_SHA256="5117f930900b341493827d63aa910ff5e011e0b994197c3b71c08a20228a42df"
 PKG_LICENSE="GPL"
 PKG_SITE="http://tukaani.org/xz/"
-PKG_URL="http://tukaani.org/xz/$PKG_NAME-$PKG_VERSION.tar.bz2"
+PKG_URL="http://tukaani.org/xz/${PKG_NAME}-${PKG_VERSION}.tar.bz2"
 PKG_DEPENDS_HOST="ccache:host"
 PKG_DEPENDS_TARGET="toolchain"
 PKG_LONGDESC="A free general-purpose data compression software with high compression ratio."
@@ -25,5 +25,5 @@ PKG_CONFIGURE_OPTS_HOST="--disable-shared --enable-static \
 PKG_CONFIGURE_OPTS_TARGET="--disable-shared --enable-static"
 
 post_makeinstall_target() {
-  rm -rf $INSTALL
+  rm -rf ${INSTALL}
 }
diff --git a/packages/compress/zip/package.mk b/packages/compress/zip/package.mk
index 3e16fbfcc3..7f2204afd5 100644
--- a/packages/compress/zip/package.mk
+++ b/packages/compress/zip/package.mk
@@ -6,18 +6,18 @@ PKG_VERSION="3.0"
 PKG_SHA256="f0e8bb1f9b7eb0b01285495a2699df3a4b766784c1765a8f1aeedf63c0806369"
 PKG_LICENSE="Info-ZIP"
 PKG_SITE="http://www.info-zip.org/pub/infozip/"
-PKG_URL="$SOURCEFORGE_SRC/infozip/Zip%203.x%20%28latest%29/3.0/${PKG_NAME}${PKG_VERSION/./}.tar.gz"
+PKG_URL="${SOURCEFORGE_SRC}/infozip/Zip%203.x%20%28latest%29/3.0/${PKG_NAME}${PKG_VERSION/./}.tar.gz"
 PKG_DEPENDS_TARGET="toolchain bzip2"
 PKG_LONGDESC="A compression and file packaging utility."
 PKG_TOOLCHAIN="manual"
 
 make_target() {
-  make CC=$CC CPP=$CPP RANLIB=$RANLIB AR=$AR STRIP=$STRIP LOCAL_ZIP="$CFLAGS" \
+  make CC=${CC} CPP=${CPP} RANLIB=${RANLIB} AR=${AR} STRIP=${STRIP} LOCAL_ZIP="${CFLAGS}" \
        -f unix/Makefile generic
 }
 
 makeinstall_target() {
-  mkdir -p $INSTALL/usr/bin
-    cp zip $INSTALL/usr/bin
-    $STRIP $INSTALL/usr/bin/zip
+  mkdir -p ${INSTALL}/usr/bin
+    cp zip ${INSTALL}/usr/bin
+    ${STRIP} ${INSTALL}/usr/bin/zip
 }
diff --git a/packages/compress/zlib/package.mk b/packages/compress/zlib/package.mk
index 7a86e767b7..f39e64dee8 100644
--- a/packages/compress/zlib/package.mk
+++ b/packages/compress/zlib/package.mk
@@ -6,7 +6,7 @@ PKG_VERSION="1.2.11"
 PKG_SHA256="4ff941449631ace0d4d203e3483be9dbc9da454084111f97ea0a2114e19bf066"
 PKG_LICENSE="OSS"
 PKG_SITE="http://www.zlib.net"
-PKG_URL="http://zlib.net/$PKG_NAME-$PKG_VERSION.tar.xz"
+PKG_URL="http://zlib.net/${PKG_NAME}-${PKG_VERSION}.tar.xz"
 PKG_DEPENDS_HOST="cmake:host"
 PKG_DEPENDS_TARGET="toolchain"
 PKG_LONGDESC="A general purpose (ZIP) data compression library."