diff --git a/scripts/mancheck.sh b/scripts/mancheck.sh
index 364ad1b76286..33d7d3c7155f 100755
--- a/scripts/mancheck.sh
+++ b/scripts/mancheck.sh
@@ -1,53 +1,60 @@
 #!/bin/sh
 #
 # Permission to use, copy, modify, and/or distribute this software for
 # any purpose with or without fee is hereby granted.
 #
 # THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 # WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 # MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 # ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 # WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
 # AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
 # OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 #
-# shellcheck disable=SC2086
+# shellcheck disable=SC2068,SC2086
 
 trap 'rm -f "$stdout_file" "$stderr_file" "$result_file"' EXIT
 
 if [ "$#" -eq 0 ]; then
-    echo "Usage: $0 manpage-directory..."
+    echo "Usage: $0 <manpage-directory|manpage-file>..."
     exit 1
 fi
 
 if ! command -v mandoc > /dev/null; then
     echo "skipping mancheck because mandoc is not installed"
     exit 0
 fi
 
 IFS="
 "
-files="$(find "$@" -type f -name '*[1-9]*' -not -name '.*')" || exit 1
+files="$(
+  for path in $@ ; do
+    find -L $path -type f -name '*[1-9]*' -not -name '.*'
+  done | sort | uniq
+)"
+
+if [ "$files" = "" ] ; then
+    echo no files to process! 1>&2
+    exit 1
+fi
 
 add_excl="$(awk '
     /^.\\" lint-ok:/ {
         print "-e"
         $1 = "mandoc:"
         $2 = FILENAME ":[[:digit:]]+:[[:digit:]]+:"
         print
     }' $files)"
 
 # Redirect to file instead of 2>&1ing because mandoc flushes inconsistently(?) which tears lines
 # https://github.com/openzfs/zfs/pull/12129/checks?check_run_id=2701608671#step:5:3
 stdout_file="$(mktemp)"
 stderr_file="$(mktemp)"
 mandoc -Tlint $files 1>"$stdout_file" 2>"$stderr_file"
 result_file="$(mktemp)"
 grep -vhE -e 'mandoc: outdated mandoc.db' -e 'STYLE: referenced manual not found' $add_excl "$stdout_file" "$stderr_file" > "$result_file"
 
 if [ -s "$result_file" ]; then
     cat "$result_file"
     exit 1
-else
-    echo "no errors found"
 fi