feat(travis): run shellcheck during lint job

* saltstack-formulas/template-formula#180 (comment)

.travis.yml

@@ -24,7 +24,7 @@ jobs:
     - language: 'node_js'
       node_js: 'lts/*'
       env: 'Lint'
-      name: 'Lint: salt-lint, yamllint, rubocop & commitlint'
+      name: 'Lint: salt-lint, yamllint, rubocop, shellcheck & commitlint'
       before_install: 'skip'
       script:
         # Install and run `salt-lint`
@@ -38,6 +38,10 @@ jobs:
         # Install and run `rubocop`
         - gem install rubocop
         - rubocop -d
+        # Run `shellcheck` (already pre-installed in Travis)
+        - shellcheck --version
+        - git ls-files | grep '\.sh$\|\.bash$\|\.ksh$'
+                       | xargs shellcheck
         # Install and run `commitlint`
         - npm i -D @commitlint/config-conventional
                    @commitlint/travis-cli

ssf/defaults.yaml

@@ -22,8 +22,8 @@ ssf_node_anchors:
             #       An alternative method could be to use:
             #       `git describe --abbrev=0 --tags`
             # yamllint disable rule:line-length
-            title: 'ci(travis): use default matrix after `centos-6` image fix'
-            body: '* Automated using https://github.com/myii/ssf-formula/pull/105'
+            title: 'ci(travis): run `shellcheck` during lint job [skip ci]'
+            body: '* Automated using https://github.com/myii/ssf-formula/pull/106'
             # yamllint enable rule:line-length
           github:
             owner: 'saltstack-formulas'

ssf/files/default/.travis.yml

@@ -23,10 +23,10 @@ fast_finish: true
 
 {#-   Prepare variables used for linters #}
 {%- set comment_linters = '# Run all of the linters in a single job' %}
-{%- set name_linters = 'Lint: salt-lint, yamllint, rubocop & commitlint' %}
+{%- set name_linters = 'Lint: salt-lint, yamllint, rubocop, shellcheck & commitlint' %}
 {%- if not travis.use_single_job_for_linters %}
 {%-   set comment_linters = comment_linters ~ ' (except `rubocop`)' %}
-{%-   set name_linters = 'Lint: salt-lint, yamllint & commitlint' %}
+{%-   set name_linters = 'Lint: salt-lint, yamllint, shellcheck & commitlint' %}
 {%- endif %}
 {#-   Prepare variable used for `saltcheck` #}
 {%-   set use_saltcheck = False %}
@@ -137,6 +137,10 @@ jobs:
         {%- if travis.use_single_job_for_linters %}
         {{-   format_rubocop_linter() }}
         {%- endif %}
+        # Run `shellcheck` (already pre-installed in Travis)
+        - shellcheck --version
+        - git ls-files | grep '\.sh$\|\.bash$\|\.ksh$'
+                       | xargs shellcheck
         # Install and run `commitlint`
         - npm i -D @commitlint/config-conventional
                    @commitlint/travis-cli