Add Shellcheck to GitHub Action

Shellcheck is a static analyzer for Shell script. This commit only enables the error checks, and disables the info and warning checks. Because there would've been a lot to fix if WARNING/INFO is enabled.

This commit fixes an error detected by Shellcheck

Signed-off-by: Hanwen <[email protected]>

Author: hanwen-cluster

.github/workflows/ci.yml

@@ -79,3 +79,13 @@ jobs:
         run: pip install tox
       - name: Run Tox
         run: tox -e ${{ matrix.toxenv }}
+  shellcheck:
+    name: Shellcheck
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Run ShellCheck
+        uses: ludeeus/action-shellcheck@master
+        with:
+          severity: error
+          ignore_paths: third-party

system_tests/install_cinc.sh

@@ -22,7 +22,7 @@ elif [ `echo "${RELEASE}" | grep '^ubuntu\.20'` ]; then
   OS='ubuntu2004'
 else
   echo "Operating System '${RELEASE}' is not supported. Failing build."
-  exit -1
+  exit 1
 fi
 
 if [ `echo "${OS}" | grep -E '^(alinux|centos)'` ]; then