Fix various shellcheck warnings

Author: ribose-jeffreylau

examples/build_dir.sh

@@ -16,7 +16,7 @@ set -v # Print executed lines
 
 BUILD_DIR="${TRAVIS_BUILD_DIR:-$(mktemp -d)}/b"
 
-mkdir -p ${BUILD_DIR}
+mkdir -p "${BUILD_DIR}"
 
 # The --sudo option is typically needed when installing to standard locations.
 # Note that `sudo ./install_gpg_all …` is not the same—it would compile as
@@ -45,9 +45,9 @@ gpg --version | head -n 1 | cut -d" " -f 3 | grep -xE "2\.2\.[0-9]+"
 
 # Assert that ${BUILD_DIR} is now full of files (cause build had happened
 # there)…
-pushd ${BUILD_DIR}
+pushd "${BUILD_DIR}"
 ls -d libgpg-error-*
 ls -d gnupg-*
-[[ -f "$(ls | grep "libgpg-error-")/Makefile" ]]
-[[ -f "$(ls | grep "gnupg-")/Makefile" ]]
+ls libgpg-error-*/Makefile
+ls gnupg-*/Makefile
 popd

examples/components_individually.sh

@@ -77,17 +77,17 @@ gpg --version
 gpg --version | head -n 1 | cut -d" " -f 3 | grep -xF "2.2.20"
 
 # Assert configured algorithms (enabled SHA256 and disabled SHA512)…
-gpg --version | grep -i "SHA256"
-[[ ! $(gpg --version | grep -i "SHA512") ]]
+gpg --version | grep -q -i "SHA256"
+gpg --version | grep -q -v -i "SHA512"
 
 # Assert disabled docs for libgpg-error, and enabled for other packages…
 [[   -f "/usr/local/share/man/man1/gpg.1" ]]
 [[ ! -f "/usr/local/share/man/man1/gpg-error-config.1" ]]
 
 # Assert that building the libgcrypt component has happened in a $BUILD_DIR,
 # and no other component was built there…
-pushd ${BUILD_DIR}
+pushd "${BUILD_DIR}"
 ls -d libgcrypt-*
-[[ ! $(ls . | grep -v "libgcrypt-") ]]
-[[ -f "$(ls | grep "libgcrypt-")/Makefile" ]]
+ls libgcrypt-*
+ls libgcrypt-*/Makefile
 popd

examples/configure_options.sh

@@ -37,5 +37,5 @@ gpg --version | head -n 1 | cut -d" " -f 3 | grep -xE "2\.2\.[0-9]+"
 [[ ! -f "/usr/local/share/man/man7/gnupg.7" ]]
 
 # Assert configured algorithms (enabled SHA256 and disabled SHA512)…
-gpg --version | grep -i "SHA256"
+gpg --version | grep -q -i "SHA256"
 gpg --version | grep -q -v -i "SHA512"

examples/install_prefix.sh

@@ -30,7 +30,7 @@ GPG_CONFIGURE_OPTS="--prefix=${GPG_PREFIX} \
 # provided with $PATH and $GPG_PREFIX, hence we must enhance $PATH.
 export PATH="${EXEC_PREFIX}/bin:${PATH}"
 
-mkdir -p ${GPG_PREFIX} ${EXEC_PREFIX} ${MAN_DIR}
+mkdir -p "${GPG_PREFIX}" "${EXEC_PREFIX}" "${MAN_DIR}"
 
 # The --ldconfig option is typically needed on GNU+Linux systems.  It causes
 # `ldconfig` to be run right after installing each component in order to

examples/no_sudo.sh

@@ -27,7 +27,7 @@ export LD_RUN_PATH="${GPG_PREFIX}/lib:${LD_RUN_PATH}"
 # provided with $PATH and $GPG_PREFIX, hence we must enhance $PATH.
 export PATH="${GPG_PREFIX}/bin:${PATH}"
 
-mkdir -p ${GPG_PREFIX}
+mkdir -p "${GPG_PREFIX}"
 
 ./install_gpg_all.sh --suite-version latest --no-sudo \
 	--configure-opts "${GPG_CONFIGURE_OPTS}" "$@"