diff --git a/.github/workflows/gradle.yml b/.github/workflows/gradle.yml
index a2c74cd0..3effeb31 100644
--- a/.github/workflows/gradle.yml
+++ b/.github/workflows/gradle.yml
@@ -41,7 +41,7 @@ jobs:
       if: github.event_name == 'pull_request'
       run: |
         git fetch --depth=1 origin ${{github.base_ref}}
-        scripts/check-copyright.sh origin/${{github.base_ref}}
+        scripts/check-copyright.sh -- origin/${{github.base_ref}}
     - name: Build with Gradle
       run: ./gradlew build
     - name: Upload test reports
diff --git a/scripts/check-copyright.sh b/scripts/check-copyright.sh
index a58ac167..4b18f411 100755
--- a/scripts/check-copyright.sh
+++ b/scripts/check-copyright.sh
@@ -16,103 +16,136 @@
 #
 # SPDX-License-Identifier: Apache-2.0
 
-# Stop on first unexpected error
-set -e
-
-die() {
-  echo "$@" >&2
-  exit 1
-}
-
-# Check that git is a command
-command -v git > /dev/null 2>&1 || die "Can not find 'git' command."
-
-# Check that base ref has been specified
-[ -n "$1" ] || die "Missing required first parameter: git-base-ref"
-BASE="$1"
-
-# Check it is a valid ref
-git rev-parse --quiet --verify "$BASE" > /dev/null || die "Specified git base ref '$BASE' is not a valid ref in this repository."
-
-# git uses the following one-character change status codes
-# A - Added
-# C - Copied
-# D - Deleted
-# M - Modified
-# R - Renamed
-
-# Keep track of how many files failed the copyright check so we can find them all and return 0 if there were none
-FAILED=0
-
-# Copy stdout to another file descriptor for logging
-exec 3>&1
-log() { echo>&3 "$@"; }
-
-# Look for unsupported changes with Broken (B), changed (T), Unmerged (U), or Unknown (X) status
-BAD_FILES="$(git diff --name-status --diff-filter=BTUX "$BASE")"
-
-[ -z "$BAD_FILES" ] || {
-  echo "‼️ This script ($0) may need fixing to deal with more types of change." >&2
-  echo "$BAD_FILES" | sed 's/^/🤯 Unsupported change type: /'
-  FAILED=$(( FAILED + $(echo "$BAD_FILES"|wc -l) ))
-}
-
-# Print deleted files, just for completeness
-git diff --name-only --diff-filter=D "$BASE" | sed 's/^/🫥 Ignoring deleted file: /'
-
-
-# Function to print each file from stdin to stdout unless it has good copyright
-badCopyrightFilter() {
-  while read filePath; do
-    [ -f "$filePath" ] || die "Cannot check copyright in non-existent file: '$filePath'"
-    grep -Eq "SPDX-License-Identifier: Apache-2.0" "$filePath" || {
-      log "👿 License identifier not found: $filePath"
-      echo "$filePath"
-      continue
-    }
-    yearModified=`git log -1 --pretty=format:%cd --date=format:%Y -- "$filePath"`
-    grep -Eq "Copyright $yearModified IBM Corporation and" "$filePath" && log "😅 Copyright OK: $filePath" || {
-      existingModifiedYear="$(grep -Eo 'Copyright [0-9]{4} IBM Corporation and' "$filePath" | cut -d ' ' -f 2 )"
-      case "$existingModifiedYear" in
-        "$yearModified") continue ;;
-        "")              log "🤬 No copyright year in '$filePath': expected '$yearModified'." ;;
-        *)               log "😡 Wrong copyright year in '$filePath': expected '$yearModified' but found '$existingModifiedYear'." ;;
-      esac
-      echo "$filePath"
-    }
-  done
-}
-
-echo "Checking added and modified files..."
-FAILED=$((FAILED + $(git diff --name-only --find-copies-harder --diff-filter=AM "$BASE" | badCopyrightFilter | wc -l)))
-
-
-# Renamed (R) and copied (C) files are more complicated.
-# They can report as less than 100% identical even when their contents are the same.
-# This is apparently due to metadata changes. Shrug.
-# So check whether the contents have changed significantly.
-
-# Define how to compare a file against its origin for significant content changes.
-# Succeed if there are differences, and print the filename.
-isReallyDifferent() { ! git diff --ignore-all-space --quiet "$1" "$2" 2>/dev/null && echo "$2"; }
-
-# Read status, source, and destination as separate records (lines).
-# Check the status is R... or C... (otherwise it was parsed incorrectly).
-# Then compare the source and dest for significant differences.
-# Lastly, if they were different, check them for copyright.
-badCopyrightFilter2() {
-  while read status && read src && read dst
-  do
-    case "$status" in
-    R*) isReallyDifferent "$BASE:$src" "$dst" || log "🫥 Ignoring renamed file: $src -> $dst" ;;
-    C*) isReallyDifferent "$BASE:$src" "$dst" || log "🫥 Ignoring copied file: $src -> $dst" ;;
-    *) die "Unexpected status while parsing git diff output: status='$status' src='$src' dst='$dst'" ;;
+# Enforce top-level subshell to avoid leaking environment changes (in case script is sourced)
+(
+  # Stop on first unexpected error
+  set -e
+
+  usage() {
+    echo "usage:\t$0 [-q|--quiet|-t|--terse|-v|--verbose] git-base-ref"
+    echo "\t-h,--help\tprints this usage info"
+    echo "\t-t,--terse\tsuppresses all informational outpout"
+    echo "\t-q,--quiet\tsuppresses all non-error outpout"
+    echo "\t-v,--verbose\tenables verbose output"
+  }
+
+  # Copy stdout and stderr to other file descriptors for logging and error reporting
+  exec 3>/dev/null 4>&1 5>&1 6>&2
+  # Define semantic functions to echo or cat messages to the various file descriptors
+  echocat() { { [ $# -gt 0 ] && echo "$@"; } || cat; }
+  log() { echocat "$@" >&3; }
+  inf() { echocat "$@" >&4; }
+  wrn() { echocat "$@" >&5; }
+  err() { echocat "$@" >&6; }
+  # Define a Perl-style "die" function to emit an error message and exit with an error code
+  die() {
+    err "$@"
+    exit 1
+  }
+
+  # Parse script options
+  while [ $# -gt 0 ]; do
+    case "$1" in
+      # -t disables logging and info
+      -h|--help) usage; exit 0;;
+      # -t disables logging and info
+      -t|--terse)   exec 3>/dev/null 4>/dev/null 5>&2;        shift;;
+      # -q disables logging, info, and warning
+      -q|--quiet)   exec 3>/dev/null 4>/dev/null 5>/dev/null; shift;;
+      # -v enables logging
+      -v|--verbose) exec 3>&1        4>&1        5>&2;        shift;;
+      # -- indicates the explicit end of options, so consume it and exit the loop
+      --) shift; break;;
+      # any other option-like string is an error
+      -*) err "$0: unknown option '$1'"; usage | die;;
+      # any non-option-like string indicates the end of the options
+      *) break;;
     esac
-  done | badCopyrightFilter
-}
-
-echo "Checking renamed and copied files..."
-OUTPUT="$(git diff --name-status --find-copies-harder --diff-filter=CR -z "$BASE" 2>/dev/null | tr '\0' '\n')"
-FAILED=$((FAILED + $(echo "$OUTPUT"| badCopyrightFilter2 | wc -l)))
+  done
 
-exit $FAILED
+  # Check that git is a command
+  command -v git > /dev/null 2>&1 || die "Can not find 'git' command."
+
+  # Check that base ref has been specified
+  [ -n "$1" ] || die "Missing required first parameter: git-base-ref"
+  BASE="$1"
+
+  # Check it is a valid ref
+  git rev-parse --quiet --verify "$BASE" > /dev/null || die "Specified git base ref '$BASE' is not a valid ref in this repository."
+
+  # Git uses the following one-character change status codes
+  # A - Added
+  # C - Copied
+  # D - Deleted
+  # M - Modified
+  # R - Renamed
+
+  # Keep track of how many files failed the copyright check so we can find them all and return 0 if there were none
+  FAILED=0
+
+  # Look for unsupported changes with Broken (B), changed (T), Unmerged (U), or Unknown (X) status
+  BAD_FILES="$(git diff --name-status --diff-filter=BTUX "$BASE")"
+
+  [ -z "$BAD_FILES" ] || {
+    err "‼️ This script ($0) may need fixing to deal with more types of change."
+    echo "$BAD_FILES" | sed 's/^/🤯 Unsupported change type: /' | err
+    FAILED=$(( FAILED + $(echo "$BAD_FILES"|wc -l) ))
+  }
+
+  # Log deleted files
+  git diff --name-only --diff-filter=D "$BASE" | sed 's/^/🫥 Ignoring deleted file: /' | log
+
+  # Function to print each file from stdin to stdout unless it has good copyright
+  badCopyrightFilter() {
+    while read filePath; do
+      [ -f "$filePath" ] || die "Cannot check copyright in non-existent file: '$filePath'"
+      grep -Eq "SPDX-License-Identifier: Apache-2.0" "$filePath" || {
+        wrn "👿 License identifier not found: $filePath"
+        echo "$filePath"
+        continue
+      }
+      yearModified=`git log -1 --pretty=format:%cd --date=format:%Y -- "$filePath"`
+      grep -Eq "Copyright $yearModified IBM Corporation and" "$filePath" && inf "😅 Copyright OK: $filePath" || {
+        existingModifiedYear="$(grep -Eo 'Copyright [0-9]{4} IBM Corporation and' "$filePath" | cut -d ' ' -f 2 )"
+        case "$existingModifiedYear" in
+          "$yearModified") continue ;;
+          "")              wrn "🤬 No copyright year in '$filePath': expected '$yearModified'." ;;
+          *)               wrn "😡 Wrong copyright year in '$filePath': expected '$yearModified' but found '$existingModifiedYear'." ;;
+        esac
+        echo "$filePath"
+      }
+    done
+  }
+
+  inf "Checking added and modified files..."
+  FAILED=$((FAILED + $(git diff --name-only --find-copies-harder --diff-filter=AM "$BASE" | badCopyrightFilter | wc -l)))
+
+  # Renamed (R) and copied (C) files are more complicated.
+  # They can report as less than 100% identical even when their contents are the same.
+  # This is apparently due to metadata changes. Shrug.
+  # So check whether the contents have changed significantly.
+
+  # Define how to compare a file against its origin for significant content changes.
+  # Succeed if there are differences, and print the filename.
+  isReallyDifferent() { ! git diff --ignore-all-space --quiet "$1" "$2" 2>/dev/null && echo "$2"; }
+
+  # Read status, source, and destination as separate records (lines).
+  # Check the status is R... or C... (otherwise it was parsed incorrectly).
+  # Then compare the source and dest for significant differences.
+  # Lastly, if they were different, check them for copyright.
+  badCopyrightFilter2() {
+    while read status && read src && read dst
+    do
+      case "$status" in
+        R*) isReallyDifferent "$BASE:$src" "$dst" || log "🫥 Ignoring renamed file: $src -> $dst" ;;
+        C*) isReallyDifferent "$BASE:$src" "$dst" || log "🫥 Ignoring copied file: $src -> $dst" ;;
+        *) die "Unexpected status while parsing git diff output: status='$status' src='$src' dst='$dst'" ;;
+      esac
+    done | badCopyrightFilter
+  }
+
+  inf "Checking renamed and copied files..."
+  OUTPUT="$(git diff --name-status --find-copies-harder --diff-filter=CR -z "$BASE" 2>/dev/null | tr '\0' '\n')"
+  FAILED=$((FAILED + $(echo "$OUTPUT"| badCopyrightFilter2 | wc -l)))
+  exit $FAILED
+)