diff --git a/src/scripts/merge_tools/check-implementations.sh b/src/scripts/merge_tools/check-implementations.sh
index 6266b17e3b..623a7f6d42 100755
--- a/src/scripts/merge_tools/check-implementations.sh
+++ b/src/scripts/merge_tools/check-implementations.sh
@@ -4,8 +4,12 @@
 
 set -e
 
+SCRIPTDIR="$(cd "$(dirname "$0")" && pwd -P)"
+
 # Check for identical content.
 
+cd "$SCRIPTDIR"
+
 diff -q ivn_plus.sh adjacent_plus.sh > /dev/null 2>&1 && { echo "identical: ivn_plus.sh adjacent_plus.sh"; exit 1; }
 diff -q ivn_plus.sh gitmerge_ort_plus.sh
 diff -q ivn_plus.sh imports_plus.sh
@@ -26,25 +30,25 @@ tmpfile2=$(mktemp)
 
 for base in adjacent imports ivn version_numbers ; do
     diff "$base.sh" "${base}_ignorespace.sh" > "$tmpfile" || true
-    diff -q diff-pl-ignorespace.diff "$tmpfile" || { echo "problem with: diff $base.sh ${base}_ignorespace.sh" ; exit 1; }
+    diff -q diff-pl-ignorespace.diff "$tmpfile" || { echo "problem with: diff $base.sh ${base}_ignorespace.sh, expected to be as in diff-pl-ignorespace.diff" ; exit 1; }
     diff "${base}_plus.sh" "${base}_ignorespace_plus.sh" > "$tmpfile" || true
-    diff -q diff-pl-ignorespace.diff "$tmpfile" || { echo "problem with: diff ${base}_plus.sh ${base}_ignorespace_plus.sh" ; exit 1; }
+    diff -q diff-pl-ignorespace.diff "$tmpfile" || { echo "problem with: diff ${base}_plus.sh ${base}_ignorespace_plus.sh, expected to be as in diff-pl-ignorespace.diff" ; exit 1; }
 
     diff "$base.sh" "${base}_plus.sh" > "$tmpfile" || true
     diff "${base}_ignorespace.sh" "${base}_ignorespace_plus.sh" > "$tmpfile2" || true
-    diff -q "$tmpfile" "$tmpfile2" || { echo "problem with: ( $base.sh ${base}_plus.sh) versus ( ${base}_ignorespace.sh ${base}_ignorespace_plus.sh"; exit 1; }
+    diff -q "$tmpfile" "$tmpfile2" || { echo "problem with: ( $base.sh ${base}_plus .sh) versus ( ${base}_ignorespace.sh ${base}_ignorespace_plus.sh )"; exit 1; }
 done
 
 
 for base in gitmerge_ort gitmerge_recursive_myers ; do
     diff "$base.sh" "${base}_ignorespace.sh" > "$tmpfile" || true
     diff "${base}_plus.sh" "${base}_ignorespace_plus.sh" > "$tmpfile2" || true
-    diff -q "$tmpfile" "$tmpfile2" || { echo "problem with: ( $base.sh ${base}_ignorespace.sh) versus ( ${base}_plus.sh ${base}_ignorespace_plus.sh"; exit 1; }
+    diff -q "$tmpfile" "$tmpfile2" || { echo "problem with: ( $base.sh ${base}_ignorespace.sh ) versus ( ${base}_plus.sh ${base}_ignorespace_plus.sh )"; exit 1; }
 
 
     diff "$base.sh" "${base}_plus.sh" > "$tmpfile" || true
     diff "${base}_ignorespace.sh" "${base}_ignorespace_plus.sh" > "$tmpfile2" || true
-    diff -q "$tmpfile" "$tmpfile2" || { echo "problem with: ( $base.sh ${base}_plus.sh) versus ( ${base}_ignorespace.sh ${base}_ignorespace_plus.sh"; exit 1; }
+    diff -q "$tmpfile" "$tmpfile2" || { echo "problem with: ( $base.sh ${base}_plus.sh ) versus ( ${base}_ignorespace.sh ${base}_ignorespace_plus.sh )"; exit 1; }
 done
 
 
@@ -56,7 +60,7 @@ for base in gitmerge_recursive_histogram gitmerge_recursive_minimal \
             gitmerge_recursive_patience ; do
 
     diff "$base.sh" "${base}_plus.sh" > "$tmpfile" || true
-    diff -q diff-gm-plus.diff "$tmpfile" || { echo "problem with $base.sh ${base}_plus.sh"; exit 1; }
+    diff -q diff-gm-plus.diff "$tmpfile" || { echo "problem with $base.sh ${base}_plus.sh, expected to be as in diff-gm-plus.diff"; exit 1; }
 
 done
 
diff --git a/src/scripts/merge_tools/diff-gm-plus.diff b/src/scripts/merge_tools/diff-gm-plus.diff
index ad271b1ce4..7b877e6c50 100644
--- a/src/scripts/merge_tools/diff-gm-plus.diff
+++ b/src/scripts/merge_tools/diff-gm-plus.diff
@@ -1,5 +1,10 @@
-10c10,11
+6a7
+> verbose=
+7a9
+>   verbose="$1"
+15c17,19
 < "$MERGE_SCRIPTS_DIR"/gitmerge.sh "$clone_dir" "$branch1" "$branch2" "$git_strategy"
 ---
 > plumelib_strategy=""
-> "$MERGE_SCRIPTS_DIR"/merge_git_then_plumelib.sh "$clone_dir" "$branch1" "$branch2" "$git_strategy" "$plumelib_strategy"
+> # shellcheck disable=SC2086 # '$verbose' should not be quoted
+> "$MERGE_SCRIPTS_DIR"/merge_git_then_plumelib.sh $verbose "$clone_dir" "$branch1" "$branch2" "$git_strategy" "$plumelib_strategy"
diff --git a/src/scripts/merge_tools/diff-pl-ignorespace.diff b/src/scripts/merge_tools/diff-pl-ignorespace.diff
index 87a9cfc3ee..92d4c15593 100644
--- a/src/scripts/merge_tools/diff-pl-ignorespace.diff
+++ b/src/scripts/merge_tools/diff-pl-ignorespace.diff
@@ -1,4 +1,4 @@
-9c9
+16c16
 < git_strategy="-s ort"
 ---
 > git_strategy="-s ort -Xignore-space-change"
diff --git a/src/scripts/merge_tools/gitmerge_ort.sh b/src/scripts/merge_tools/gitmerge_ort.sh
index 22d3b7580e..b30f879b0a 100755
--- a/src/scripts/merge_tools/gitmerge_ort.sh
+++ b/src/scripts/merge_tools/gitmerge_ort.sh
@@ -4,7 +4,9 @@
 
 MERGE_SCRIPTS_DIR="$(cd "$(dirname "$0")" && pwd -P)"
 
+
 if [ "$1" = "--verbose" ] ; then
+
   shift
 fi
 
diff --git a/src/scripts/merge_tools/gitmerge_ort_ignorespace.sh b/src/scripts/merge_tools/gitmerge_ort_ignorespace.sh
index f836c0e836..f3f013c366 100755
--- a/src/scripts/merge_tools/gitmerge_ort_ignorespace.sh
+++ b/src/scripts/merge_tools/gitmerge_ort_ignorespace.sh
@@ -4,7 +4,9 @@
 
 MERGE_SCRIPTS_DIR="$(cd "$(dirname "$0")" && pwd -P)"
 
+
 if [ "$1" = "--verbose" ] ; then
+
   shift
 fi
 
diff --git a/src/scripts/merge_tools/gitmerge_recursive_myers.sh b/src/scripts/merge_tools/gitmerge_recursive_myers.sh
index e34cf60558..865017930a 100755
--- a/src/scripts/merge_tools/gitmerge_recursive_myers.sh
+++ b/src/scripts/merge_tools/gitmerge_recursive_myers.sh
@@ -4,7 +4,9 @@
 
 MERGE_SCRIPTS_DIR="$(cd "$(dirname "$0")" && pwd -P)"
 
+
 if [ "$1" = "--verbose" ] ; then
+
   shift
 fi
 
diff --git a/src/scripts/merge_tools/gitmerge_recursive_myers_ignorespace.sh b/src/scripts/merge_tools/gitmerge_recursive_myers_ignorespace.sh
index 3e6e7f0107..6550919158 100755
--- a/src/scripts/merge_tools/gitmerge_recursive_myers_ignorespace.sh
+++ b/src/scripts/merge_tools/gitmerge_recursive_myers_ignorespace.sh
@@ -4,7 +4,9 @@
 
 MERGE_SCRIPTS_DIR="$(cd "$(dirname "$0")" && pwd -P)"
 
+
 if [ "$1" = "--verbose" ] ; then
+
   shift
 fi