diff --git a/development/CI/bin/check_git_log_for_unrecognised_email_addresses.sh b/development/CI/bin/check_git_log_for_unrecognised_email_addresses.sh
index d6ca54794b..5b6646c695 100755
--- a/development/CI/bin/check_git_log_for_unrecognised_email_addresses.sh
+++ b/development/CI/bin/check_git_log_for_unrecognised_email_addresses.sh
@@ -3,36 +3,44 @@
 #
 CMD=$1
 SINCE_DATE=2015-01-01
+# Set format of output as follows:
+#       abbrev-hash  author-date(ISO8601-like)  author-name  author-email
 FORMAT='%h %ai name=%an email=%ae'
+# For portability/robustness, explicitly set n:o digits in commit hash (%h)
+HASH_ABBREV=10
 SCRIPT=$0
 
 function show_help() {
     cat <<EOF
 SCRIPT=$SCRIPT
 
-This script filters the git log for commits whose
-author's e-mail is _not_ on @lyx.org.
+Script to filter the git log for commits whose author's e-mail is
+_not_ on @lyx.org. It's intended to be used by a CI job.
 
 This script can be used to check that the LyX developers have
 correctly configured their git to provide an e-mail address that's in
 the @lyx.org domain. This is needed for proper functioning of the
 e-mails being automatically sent to lyx-cvs@lyx.org.
 
+Syntax:
+    <SCRIPT> { --help | -h | --list | -l | --compute-hash }
+    <SCRIPT> { --check-hash | -c }  <EXPECTED-HASH>
+
 Examples:
-	# List contributions from non-@lyx.org-addresses since 2015-01-01
-	$SCRIPT --list
+    # Show this help text
+	<SCRIPT> -h
+
+    # List contributions from non-@lyx.org-addresses since 2015-01-01
+	<SCRIPT> --list
 
     # Compute hash (SHA-512) of list of contributors
-	$SCRIPT --compute-hash
+	<SCRIPT> --compute-hash
 
     # Check hash of list of contributors against expected hash.
     # This scripts exist with a non-zero error code if hash does not match.
-	$SCRIPT --check-hash \
+	<SCRIPT> --check-hash \
         1330d9fca5e385e9de8933cbf6d391222207b2f6af1cf7ca3175babfd4e5ab46b024ff2d98c7c8630b362be506da9376f9262a524755f9acf655d83dcce8a564
 
-    # Show help text
-	$SCRIPT -h
-
 Background:
 See e-mail thread on developers@lyx.org started by Scott 2017-07-30.
 EOF
@@ -45,13 +53,13 @@ function fail() {
 }
 
 function list_filtered_git_log() {
-    git log --since=$SINCE_DATE --format="$FORMAT" \
+    git log --since=$SINCE_DATE --format="$FORMAT" --abbrev=$HASH_ABBREV \
         | grep -v 'lyx\.org$'
 }
 
 function compute_current_hash() {
     FILTERED_LOG=$( list_filtered_git_log )
-    echo "$FILTERED_LOG" | shasum -a 512 | cut -d ' ' -f 1
+    CURRENT_HASH=$( echo "$FILTERED_LOG" | shasum -a 512 | cut -d ' ' -f 1 )
 }
 
 case "$CMD" in
@@ -65,16 +73,17 @@ case "$CMD" in
         ;;
 
     "--compute-hash")
-        CURRENT_HASH=$( compute_current_hash )
+        compute_current_hash
         printf "Current hash: %s\n" "$CURRENT_HASH"
         exit 0
         ;;
 
     "-c"|"--check-hash")
         DESIRED_HASH=$2
-        CURRENT_HASH=$( compute_current_hash )
+        [[ "$DESIRED_HASH" == "" ]] && fail "No expected hash value was provided."
+        compute_current_hash
         if [[ "$CURRENT_HASH" == "$DESIRED_HASH" ]]; then
-            printf "Hash matches current hash\n:"
+            printf "Hash of filtered git log matches that of the provided expected hash\n:"
             printf "  Current: %s\n" "$CURRENT_HASH"
             exit 0;
         else