Assorted shellcheck cleanup. (#14524)

* Add shellcheck config file to globally disable dead code checks.

These checks have an extremely high false positive rate and even when
they’re correctly flagging code the impact is generally very low.

* Fix assorted shellcheck errors in installer code.

This should make reviewing PRs relating to this code much easier.

* Make shellcheck quit complaining about shellcheckrc formatting.

5 files changed, 27 insertions, 5 deletions

diff --git a/packaging/installer/dependencies/centos.sh b/packaging/installer/dependencies/centos.sh
index a05bce8f01..1e44a9ffa4 100755
--- a/packaging/installer/dependencies/centos.sh
+++ b/packaging/installer/dependencies/centos.sh
@@ -96,7 +96,7 @@ check_flags() {
 
 validate_tree_centos() {
   local opts=
-  export local package_manager=
+  package_manager=
   if [[ "${NON_INTERACTIVE}" == "1" ]]; then
     echo >&2 "Running in non-interactive mode"
     opts="-y"
diff --git a/packaging/installer/functions.sh b/packaging/installer/functions.sh
index 3efaca528d..1f121da4de 100644
--- a/packaging/installer/functions.sh
+++ b/packaging/installer/functions.sh
@@ -411,7 +411,7 @@ get_group(){
   if command -v getent > /dev/null 2>&1; then
     getent group "${1:-""}"
   else
-    cat /etc/group | grep "^${1}:" 
+    grep "^${1}:" /etc/group
   fi
 }
 
@@ -600,7 +600,7 @@ install_netdata_service() {
         echo >&2 "Note: To explicitly enable netdata automatic start, set 'netdata_enable' to 'YES' in /etc/rc.conf"
         echo >&2 ""
 
-        return ${myret}
+        return "${myret}"
 
       elif issystemd; then
         # systemd is running on this system
diff --git a/packaging/installer/install-required-packages.sh b/packaging/installer/install-required-packages.sh
index c906cce34f..a4b93028b8 100755
--- a/packaging/installer/install-required-packages.sh
+++ b/packaging/installer/install-required-packages.sh
@@ -1376,6 +1376,7 @@ validate_tree_freebsd() {
   echo >&2 " > Checking for gmake ..."
   if ! pkg query %n-%v | grep -q gmake; then
     if prompt "gmake is required to build on FreeBSD and is not installed. Shall I install it?"; then
+      # shellcheck disable=2086
       run ${sudo} pkg install ${opts} gmake
     fi
   fi
@@ -1425,13 +1426,16 @@ validate_tree_centos() {
     echo >&2 " > Checking for config-manager ..."
     if ! run ${sudo} dnf config-manager --help; then
       if prompt "config-manager not found, shall I install it?"; then
+        # shellcheck disable=2086
         run ${sudo} dnf ${opts} install 'dnf-command(config-manager)'
       fi
     fi
 
     echo >&2 " > Checking for CRB ..."
+    # shellcheck disable=2086
     if ! run dnf ${sudo} repolist | grep CRB; then
       if prompt "CRB not found, shall I install it?"; then
+        # shellcheck disable=2086
         run ${sudo} dnf ${opts} config-manager --set-enabled crb
       fi
     fi
@@ -1439,24 +1443,29 @@ validate_tree_centos() {
     echo >&2 " > Checking for config-manager ..."
     if ! run ${sudo} yum config-manager --help; then
       if prompt "config-manager not found, shall I install it?"; then
+        # shellcheck disable=2086
         run ${sudo} yum ${opts} install 'dnf-command(config-manager)'
       fi
     fi
 
     echo >&2 " > Checking for PowerTools ..."
+    # shellcheck disable=2086
     if ! run yum ${sudo} repolist | grep PowerTools; then
       if prompt "PowerTools not found, shall I install it?"; then
+        # shellcheck disable=2086
         run ${sudo} yum ${opts} config-manager --set-enabled powertools
       fi
     fi
 
     echo >&2 " > Updating libarchive ..."
+    # shellcheck disable=2086
     run ${sudo} yum ${opts} install libarchive
 
   elif [[ "${version}" =~ ^7(\..*)?$ ]]; then
     echo >&2 " > Checking for EPEL ..."
     if ! rpm -qa | grep epel-release > /dev/null; then
       if prompt "EPEL not found, shall I install it?"; then
+        # shellcheck disable=2086
         run ${sudo} yum ${opts} install epel-release
       fi
     fi
@@ -1465,6 +1474,7 @@ validate_tree_centos() {
     echo >&2 " > Checking for Okay ..."
     if ! rpm -qa | grep okay > /dev/null; then
       if prompt "okay not found, shall I install it?"; then
+        # shellcheck disable=2086
         run ${sudo} yum ${opts} install http://repo.okay.com.mx/centos/6/x86_64/release/okay-release-1-3.el6.noarch.rpm
       fi
     fi
@@ -1627,7 +1637,7 @@ install_equo() {
 PACMAN_DB_SYNCED=0
 validate_install_pacman() {
 
-  if [ ${PACMAN_DB_SYNCED} -eq 0 ]; then
+  if [ "${PACMAN_DB_SYNCED}" -eq 0 ]; then
     echo >&2 " > Running pacman -Sy to sync the database"
     local x
     x=$(pacman -Sy)
diff --git a/packaging/installer/netdata-uninstaller.sh b/packaging/installer/netdata-uninstaller.sh
index 2f2e89ffdc..419002e6a6 100755
--- a/packaging/installer/netdata-uninstaller.sh
+++ b/packaging/installer/netdata-uninstaller.sh
@@ -239,15 +239,18 @@ if [ -x "$(command -v apt-get)" ] && [ "${INSTALL_TYPE}" = "binpkg-deb" ]; then
   if dpkg -s netdata > /dev/null; then
     echo "Found netdata native installation"
     if user_input "Do you want to remove netdata? "; then
+      # shellcheck disable=SC2086
       apt-get remove netdata ${FLAG}
     fi
     if dpkg -s netdata-repo-edge > /dev/null; then
       if user_input "Do you want to remove netdata-repo-edge? "; then
+        # shellcheck disable=SC2086
         apt-get remove netdata-repo-edge ${FLAG}
       fi
     fi
     if dpkg -s netdata-repo > /dev/null; then
       if user_input "Do you want to remove netdata-repo? "; then
+        # shellcheck disable=SC2086
         apt-get remove netdata-repo ${FLAG}
       fi
     fi
@@ -257,15 +260,18 @@ elif [ -x "$(command -v dnf)" ] && [ "${INSTALL_TYPE}" = "binpkg-rpm" ]; then
   if rpm -q netdata > /dev/null; then
     echo "Found netdata native installation."
     if user_input "Do you want to remove netdata? "; then
+      # shellcheck disable=SC2086
       dnf remove netdata ${FLAG}
     fi
     if rpm -q netdata-repo-edge > /dev/null; then
       if user_input "Do you want to remove netdata-repo-edge? "; then
+        # shellcheck disable=SC2086
         dnf remove netdata-repo-edge ${FLAG}
       fi
     fi
     if rpm -q netdata-repo > /dev/null; then
       if user_input "Do you want to remove netdata-repo? "; then
+        # shellcheck disable=SC2086
         dnf remove netdata-repo ${FLAG}
       fi
     fi
@@ -275,15 +281,18 @@ elif [ -x "$(command -v yum)" ] && [ "${INSTALL_TYPE}" = "binpkg-rpm" ]; then
   if rpm -q netdata > /dev/null; then
     echo "Found netdata native installation."
     if user_input "Do you want to remove netdata? "; then
+      # shellcheck disable=SC2086
       yum remove netdata ${FLAG}
     fi
     if rpm -q netdata-repo-edge > /dev/null; then
       if user_input "Do you want to remove netdata-repo-edge? "; then
+        # shellcheck disable=SC2086
         yum remove netdata-repo-edge ${FLAG}
       fi
     fi
     if rpm -q netdata-repo > /dev/null; then
       if user_input "Do you want to remove netdata-repo? "; then
+        # shellcheck disable=SC2086
         yum remove netdata-repo ${FLAG}
       fi
     fi
@@ -296,15 +305,18 @@ elif [ -x "$(command -v zypper)" ] && [ "${INSTALL_TYPE}" = "binpkg-rpm" ]; then
   if zypper search -i netdata > /dev/null; then
     echo "Found netdata native installation."
     if user_input "Do you want to remove netdata? "; then
+      # shellcheck disable=SC2086
       zypper ${FLAG} remove netdata
     fi
     if zypper search -i netdata-repo-edge > /dev/null; then
       if user_input "Do you want to remove netdata-repo-edge? "; then
+        # shellcheck disable=SC2086
         zypper ${FLAG} remove netdata-repo-edge
       fi
     fi
     if zypper search -i netdata-repo > /dev/null; then
       if user_input "Do you want to remove netdata-repo? "; then
+        # shellcheck disable=SC2086
         zypper ${FLAG} remove netdata-repo
       fi
     fi
diff --git a/packaging/makeself/install-or-update.sh b/packaging/makeself/install-or-update.sh
index 52a23fc706..62089f4e98 100755
--- a/packaging/makeself/install-or-update.sh
+++ b/packaging/makeself/install-or-update.sh
@@ -179,7 +179,7 @@ dir_should_be_link() {
   fi
 
   run ln -s "${t}" "${d}"
-  cd "${old}"
+  cd "${old}" || true
 }
 
 dir_should_be_link . bin sbin