diff --git a/.github/workflows/shellcheck.yml b/.github/workflows/shellcheck.yml
index 9e58ae1..b3b579a 100644
--- a/.github/workflows/shellcheck.yml
+++ b/.github/workflows/shellcheck.yml
@@ -1,6 +1,24 @@
+# Runs shellcheck on code -- in error mode only.
+# "paths-ignore" should be in line with unit_test.*yml files
 ---
 name: Shellcheck
-on: [pull_request]
+
+on:
+  pull_request:
+    paths-ignore:
+      - 'utils/**'
+      - 'doc/**'
+      - 'bin/**'
+      - '**.md'
+      - '**.1'
+      - '**.html'
+      - '**.pem'
+      - '**.pdf'
+      - '**.yml'
+      - 'LICENSE'
+      - 'Dockerfile'
+      - 'Dockerfile.alpine'
+
 permissions:
   contents: read
 
diff --git a/.github/workflows/unit_tests_macos.yml b/.github/workflows/unit_tests_macos.yml
index b6f6517..507ddba 100644
--- a/.github/workflows/unit_tests_macos.yml
+++ b/.github/workflows/unit_tests_macos.yml
@@ -1,3 +1,5 @@
+# "paths-ignore" should be in line with unit_tests_ubuntu.yml
+# and shellcheck.yml
 ---
 name: CI run MacOS
 
diff --git a/.github/workflows/unit_tests_ubuntu.yml b/.github/workflows/unit_tests_ubuntu.yml
index a95bb7b..fd116ae 100644
--- a/.github/workflows/unit_tests_ubuntu.yml
+++ b/.github/workflows/unit_tests_ubuntu.yml
@@ -1,3 +1,5 @@
+# "paths-ignore" should be in line with unit_tests_macos.yml
+# and shellcheck.yml
 ---
 name: CI run Ubuntu