Merge pull request #12258 from edsantiago/xref_manpages_see_also

[CI:DOCS] Add CI check for SEE ALSO in man pages

12 files changed, 136 insertions, 11 deletions

diff --git a/docs/source/markdown/podman-auto-update.1.md b/docs/source/markdown/podman-auto-update.1.md
index 4952e09dc..755f46d70 100644
--- a/docs/source/markdown/podman-auto-update.1.md
+++ b/docs/source/markdown/podman-auto-update.1.md
@@ -141,4 +141,4 @@ $ podman auto-update
 ```
 
 ## SEE ALSO
-**[podman(1)](podman.1.md)**, **[podman-generate-systemd(1)](podman-generate-systemd.1.md)**, **[podman-run(1)](podman-run.1.md)**, sd_notify(3), systemd.unit(5)
+**[podman(1)](podman.1.md)**, **[podman-generate-systemd(1)](podman-generate-systemd.1.md)**, **[podman-run(1)](podman-run.1.md)**, **sd_notify(3)**, **[systemd.unit(5)](https://www.freedesktop.org/software/systemd/man/systemd.unit.html)**
diff --git a/docs/source/markdown/podman-build.1.md b/docs/source/markdown/podman-build.1.md
index 1367c860a..40bd7d8aa 100644
--- a/docs/source/markdown/podman-build.1.md
+++ b/docs/source/markdown/podman-build.1.md
@@ -1021,7 +1021,7 @@ If you are using `useradd` within your build script, you should pass the
 useradd to stop creating the lastlog file.
 
 ## SEE ALSO
-**[podman(1)](podman.1.md)**, **[buildah(1)](https://github.com/containers/buildah/blob/main/docs/buildah.1.md)**, **[containers-certs.d(5)](https://github.com/containers/image/blob/main/docs/containers-certs.d.5.md)**, **[containers-registries.conf(5)](https://github.com/containers/image/blob/main/docs/containers-registries.conf.5.md)**, **[crun(1)](https://github.com/containers/crun/tree/main/crun.1.md)**, **[runc(8)](https://github.com/opencontainers/runc/blob/master/man/runc.8.md)**, **[useradd(8)](https://www.unix.com/man-page/redhat/8/useradd)**, **[podman-ps(1)](podman-ps.1.md)**, **[podman-rm(1)](podman-rm.1.md)**, **[Containerfile(5)](https://github.com/containers/buildah/blob/main/docs/Containerfile.5.md)**, **[containerignore(5)](https://github.com/containers/buildah/blob/main/docs/containerignore.5.md)**
+**[podman(1)](podman.1.md)**, **[buildah(1)](https://github.com/containers/buildah/blob/main/docs/buildah.1.md)**, **[containers-certs.d(5)](https://github.com/containers/image/blob/main/docs/containers-certs.d.5.md)**, **[containers-registries.conf(5)](https://github.com/containers/image/blob/main/docs/containers-registries.conf.5.md)**, **[crun(1)](https://github.com/containers/crun/blob/main/crun.1.md)**, **[runc(8)](https://github.com/opencontainers/runc/blob/master/man/runc.8.md)**, **[useradd(8)](https://www.unix.com/man-page/redhat/8/useradd)**, **[podman-ps(1)](podman-ps.1.md)**, **[podman-rm(1)](podman-rm.1.md)**, **[Containerfile(5)](https://github.com/containers/buildah/blob/main/docs/Containerfile.5.md)**, **[containerignore(5)](https://github.com/containers/buildah/blob/main/docs/containerignore.5.md)**
 
 ## HISTORY
 Aug 2020, Additional options and .containerignore added by Dan Walsh `<dwalsh@redhat.com>`
diff --git a/docs/source/markdown/podman-completion.1.md b/docs/source/markdown/podman-completion.1.md
index 639332365..7679f74b1 100644
--- a/docs/source/markdown/podman-completion.1.md
+++ b/docs/source/markdown/podman-completion.1.md
@@ -61,4 +61,4 @@ completion output to a file and source that to the user's powershell profile.
 More information about profiles is available with **Get-Help about_Profiles**.
 
 ## SEE ALSO
-**[podman(1)](podman.1.md)**, zsh(1), fish(1), powershell(1)
+**[podman(1)](podman.1.md)**, **zsh(1)**, **fish(1)**, **powershell(1)**
diff --git a/docs/source/markdown/podman-container-cleanup.1.md b/docs/source/markdown/podman-container-cleanup.1.md
index 29e34f1cf..e58519ac3 100644
--- a/docs/source/markdown/podman-container-cleanup.1.md
+++ b/docs/source/markdown/podman-container-cleanup.1.md
@@ -51,7 +51,7 @@ $ podman container cleanup mywebserver myflaskserver 860a4b23
 ```
 
 ## SEE ALSO
-**[podman(1)](podman.1.md)**, **[podman-container(1)](podman-container.1.md)**, conmon(8)
+**[podman(1)](podman.1.md)**, **[podman-container(1)](podman-container.1.md)**, **[conmon(8)](https://github.com/containers/conmon/blob/main/docs/conmon.8.md)**
 
 ## HISTORY
 Jun 2018, Originally compiled by Dan Walsh <dwalsh@redhat.com>
diff --git a/docs/source/markdown/podman-container-runlabel.1.md b/docs/source/markdown/podman-container-runlabel.1.md
index cee20046d..7078b07e4 100644
--- a/docs/source/markdown/podman-container-runlabel.1.md
+++ b/docs/source/markdown/podman-container-runlabel.1.md
@@ -84,7 +84,7 @@ $ podman container runlabel --display run foobar
 ```
 
 ## SEE ALSO
-**[podman(1)](podman.1.md)**, **[crun(1)](https://github.com/containers/crun/tree/main/crun.1.md)**, **[runc(8)](https://github.com/opencontainers/runc/blob/master/man/runc.8.md)**, **[containers-certs.d(5)](https://github.com/containers/image/blob/main/docs/containers-certs.d.5.md)**, **[containers-auth.json(5)](https://github.com/containers/image/blob/main/docs/containers-auth.json.5.md)**, **[containers-registries.conf(5)](https://github.com/containers/image/blob/main/docs/containers-registries.conf.5.md)**
+**[podman(1)](podman.1.md)**, **[crun(1)](https://github.com/containers/crun/blob/main/crun.1.md)**, **[runc(8)](https://github.com/opencontainers/runc/blob/master/man/runc.8.md)**, **[containers-certs.d(5)](https://github.com/containers/image/blob/main/docs/containers-certs.d.5.md)**, **[containers-auth.json(5)](https://github.com/containers/image/blob/main/docs/containers-auth.json.5.md)**, **[containers-registries.conf(5)](https://github.com/containers/image/blob/main/docs/containers-registries.conf.5.md)**
 
 ## HISTORY
 August 2021, Refinements by Valentin Rothberg (rothberg at redhat dot com)
diff --git a/docs/source/markdown/podman-create.1.md b/docs/source/markdown/podman-create.1.md
index bc926875f..b0d7b8f12 100644
--- a/docs/source/markdown/podman-create.1.md
+++ b/docs/source/markdown/podman-create.1.md
@@ -1537,7 +1537,7 @@ page.
 NOTE: Use the environment variable `TMPDIR` to change the temporary storage location of downloaded container images. Podman defaults to use `/var/tmp`.
 
 ## SEE ALSO
-**[podman(1)](podman.1.md)**, **[podman-save(1)](podman-save.1.md)**, **[podman-ps(1)](podman-ps.1.md)**, **[podman-attach(1)](podman-attach.1.md)**, **[podman-pod-create(1)](podman-pod-create.1.md)**, **[podman-port(1)](podman-port.1.md)**, **[podman-start(1)](podman-start.1.md)**, **[podman-kill(1)](podman-kill.1.md)**, **[podman-stop(1)](podman-stop.1.md)**, **[podman-generate-systemd(1)](podman-generate-systemd.1.md)**, **[podman-rm(1)](podman-rm.1.md)**, **[subgid(5)](https://www.unix.com/man-page/linux/5/subuid)**, **[subuid(5)](https://www.unix.com/man-page/linux/5/subuid)**, **[containers.conf(5)](https://github.com/containers/common/blob/main/docs/containers.conf.5.md)**, **[systemd.unit(5)](https://www.freedesktop.org/software/systemd/man/systemd.unit.html)**, **[setsebool(8)](https://man7.org/linux/man-pages/man8/setsebool.8.html)**, **[slirp4netns(1)](https://github.com/rootless-containers/slirp4netns/blob/master/slirp4netns.1.md)**, **[fuse-overlayfs(1)](https://github.com/containers/fuse-overlayfs/blob/main/fuse-overlayfs.1.md)**, **proc(5)**, **[conmon(8)](https://github.com/containers/conmon/blob/main/docs/conmon.8.md)**, **personality(2)**.
+**[podman(1)](podman.1.md)**, **[podman-save(1)](podman-save.1.md)**, **[podman-ps(1)](podman-ps.1.md)**, **[podman-attach(1)](podman-attach.1.md)**, **[podman-pod-create(1)](podman-pod-create.1.md)**, **[podman-port(1)](podman-port.1.md)**, **[podman-start(1)](podman-start.1.md)**, **[podman-kill(1)](podman-kill.1.md)**, **[podman-stop(1)](podman-stop.1.md)**, **[podman-generate-systemd(1)](podman-generate-systemd.1.md)**, **[podman-rm(1)](podman-rm.1.md)**, **[subgid(5)](https://www.unix.com/man-page/linux/5/subgid)**, **[subuid(5)](https://www.unix.com/man-page/linux/5/subuid)**, **[containers.conf(5)](https://github.com/containers/common/blob/main/docs/containers.conf.5.md)**, **[systemd.unit(5)](https://www.freedesktop.org/software/systemd/man/systemd.unit.html)**, **[setsebool(8)](https://man7.org/linux/man-pages/man8/setsebool.8.html)**, **[slirp4netns(1)](https://github.com/rootless-containers/slirp4netns/blob/master/slirp4netns.1.md)**, **[fuse-overlayfs(1)](https://github.com/containers/fuse-overlayfs/blob/main/fuse-overlayfs.1.md)**, **proc(5)**, **[conmon(8)](https://github.com/containers/conmon/blob/main/docs/conmon.8.md)**, **personality(2)**
 
 ## HISTORY
 October 2017, converted from Docker documentation to Podman by Dan Walsh for Podman `<dwalsh@redhat.com>`
diff --git a/docs/source/markdown/podman-generate-systemd.1.md b/docs/source/markdown/podman-generate-systemd.1.md
index 4d1e22201..0acbb9d8c 100644
--- a/docs/source/markdown/podman-generate-systemd.1.md
+++ b/docs/source/markdown/podman-generate-systemd.1.md
@@ -235,7 +235,7 @@ CONTAINER ID  IMAGE                            COMMAND  CREATED        STATUS
 bb310a0780ae  docker.io/library/alpine:latest  /bin/sh  3 minutes ago  Created                      busy_moser
 ```
 ## SEE ALSO
-**[podman(1)](podman.1.md)**, **[podman-container(1)](podman-container.1.md)**, **systemctl(1)**, **systemd.unit(5)**, **systemd.service(5)**, **[conmon(8)](https://github.com/containers/conmon/blob/main/docs/conmon.5.md)**
+**[podman(1)](podman.1.md)**, **[podman-container(1)](podman-container.1.md)**, **systemctl(1)**, **systemd.unit(5)**, **systemd.service(5)**, **[conmon(8)](https://github.com/containers/conmon/blob/main/docs/conmon.8.md)**
 
 ## HISTORY
 April 2020, Updated details and added use case to use generated .service files as root and non-root, by Sujil Shah (sushah at redhat dot com)
diff --git a/docs/source/markdown/podman-rmi.1.md b/docs/source/markdown/podman-rmi.1.md
index 39c2e8f04..5fe0efa18 100644
--- a/docs/source/markdown/podman-rmi.1.md
+++ b/docs/source/markdown/podman-rmi.1.md
@@ -53,7 +53,6 @@ $ podman rmi -a -f
   **125** The command fails for any other reason
 
 ## SEE ALSO
-podman(1), skopeo-delete(1)
 **[podman(1)](podman.1.md)**, **[skopeo-delete(1)](https://github.com/containers/skopeo/blob/main/docs/skopeo-delete.1.md)**
 
 ## HISTORY
diff --git a/docs/source/markdown/podman-run.1.md b/docs/source/markdown/podman-run.1.md
index 6eca6b0fa..0fdd47a78 100644
--- a/docs/source/markdown/podman-run.1.md
+++ b/docs/source/markdown/podman-run.1.md
@@ -1891,7 +1891,7 @@ page.
 NOTE: Use the environment variable `TMPDIR` to change the temporary storage location of downloaded container images. Podman defaults to use `/var/tmp`.
 
 ## SEE ALSO
-**[podman(1)](podman.1.md)**, **[podman-save(1)](podman-save.1.md)**, **[podman-ps(1)](podman-ps.1.md)**, **[podman-attach(1)](podman-attach.1.md)**, **[podman-pod-create(1)](podman-pod-create.1.md)**, **[podman-port(1)](podman-port.1.md)**, **[podman-start(1)](podman-start.1.md)**, **[podman-kill(1)](podman-kill.1.md)**, **[podman-stop(1)](podman-stop.1.md)**, **[podman-generate-systemd(1)](podman-generate-systemd.1.md)**, **[podman-rm(1)](podman-rm.1.md)**, **[subgid(5)](https://www.unix.com/man-page/linux/5/subuid)**, **[subuid(5)](https://www.unix.com/man-page/linux/5/subuid)**, **[containers.conf(5)](https://github.com/containers/common/blob/main/docs/containers.conf.5.md)**, **[systemd.unit(5)](https://www.freedesktop.org/software/systemd/man/systemd.unit.html)**, **[setsebool(8)](https://man7.org/linux/man-pages/man8/setsebool.8.html)**, **[slirp4netns(1)](https://github.com/rootless-containers/slirp4netns/blob/master/slirp4netns.1.md)**, **[fuse-overlayfs(1)](https://github.com/containers/fuse-overlayfs/blob/main/fuse-overlayfs.1.md)**, **proc(5)**, **[conmon(8)](https://github.com/containers/conmon/blob/main/docs/conmon.8.md)**, **personality(2)**.
+**[podman(1)](podman.1.md)**, **[podman-save(1)](podman-save.1.md)**, **[podman-ps(1)](podman-ps.1.md)**, **[podman-attach(1)](podman-attach.1.md)**, **[podman-pod-create(1)](podman-pod-create.1.md)**, **[podman-port(1)](podman-port.1.md)**, **[podman-start(1)](podman-start.1.md)**, **[podman-kill(1)](podman-kill.1.md)**, **[podman-stop(1)](podman-stop.1.md)**, **[podman-generate-systemd(1)](podman-generate-systemd.1.md)**, **[podman-rm(1)](podman-rm.1.md)**, **[subgid(5)](https://www.unix.com/man-page/linux/5/subgid)**, **[subuid(5)](https://www.unix.com/man-page/linux/5/subuid)**, **[containers.conf(5)](https://github.com/containers/common/blob/main/docs/containers.conf.5.md)**, **[systemd.unit(5)](https://www.freedesktop.org/software/systemd/man/systemd.unit.html)**, **[setsebool(8)](https://man7.org/linux/man-pages/man8/setsebool.8.html)**, **[slirp4netns(1)](https://github.com/rootless-containers/slirp4netns/blob/master/slirp4netns.1.md)**, **[fuse-overlayfs(1)](https://github.com/containers/fuse-overlayfs/blob/main/fuse-overlayfs.1.md)**, **proc(5)**, **[conmon(8)](https://github.com/containers/conmon/blob/main/docs/conmon.8.md)**, **personality(2)**
 
 ## HISTORY
 September 2018, updated by Kunal Kushwaha `<kushwaha_kunal_v7@lab.ntt.co.jp>`
diff --git a/docs/source/markdown/podman-search.1.md b/docs/source/markdown/podman-search.1.md
index 0d72a6882..9e166fcc2 100644
--- a/docs/source/markdown/podman-search.1.md
+++ b/docs/source/markdown/podman-search.1.md
@@ -144,7 +144,6 @@ Note: This works only with registries that implement the v2 API. If tried with a
 registries.conf is the configuration file which specifies which container registries should be consulted when completing image names which do not include a registry or domain portion.
 
 ## SEE ALSO
-podman(1), containers-registries.conf(5)
 **[podman(1)](podman.1.md)**, **[containers-registries(5)](https://github.com/containers/image/blob/main/docs/containers-registries.5.md)**
 
 ## HISTORY
diff --git a/docs/source/markdown/podman.1.md b/docs/source/markdown/podman.1.md
index 20de42f1d..daa8212c5 100644
--- a/docs/source/markdown/podman.1.md
+++ b/docs/source/markdown/podman.1.md
@@ -400,7 +400,7 @@ The Network File System (NFS) and other distributed file systems (for example: L
 For more information, please refer to the [Podman Troubleshooting Page](https://github.com/containers/podman/blob/master/troubleshooting.md).
 
 ## SEE ALSO
-**[containers-mounts.conf(5)](https://github.com/containers/common/blob/main/docs/containers-mounts.conf.5.md)**, **[containers.conf(5)](https://github.com/containers/common/blob/main/docs/containers.conf.5.md)**, **[containers-registries.conf(5)](https://github.com/containers/image/blob/main/docs/containers-registries.conf.5.md)**, **[containers-storage.conf(5)](https://github.com/containers/storage/blob/main/docs/containers-storage.conf.5.md)**, **[buildah(1)](https://github.com/containers/buildah/blob/main/docs/buildah.1.md)**, **oci-hooks**(5), **[containers-policy.json(5)](https://github.com/containers/image/blob/main/docs/containers-policy.json.5.md)**, **[crun(1)](https://github.com/containers/crun/tree/main/crun.1.md)**, **[runc(8)](https://github.com/opencontainers/runc/blob/master/man/runc.8.md)**, **[subuid(5)](https://www.unix.com/man-page/linux/5/subuid)**, **[subgid(5)](https://www.unix.com/man-page/linux/5/subgid)**, **[slirp4netns(1)](https://github.com/rootless-containers/slirp4netns/blob/master/slirp4netns.1.md)**, **[conmon(8)](https://github.com/containers/conmon/blob/main/docs/conmon.8.md)**
+**[containers-mounts.conf(5)](https://github.com/containers/common/blob/main/docs/containers-mounts.conf.5.md)**, **[containers.conf(5)](https://github.com/containers/common/blob/main/docs/containers.conf.5.md)**, **[containers-registries.conf(5)](https://github.com/containers/image/blob/main/docs/containers-registries.conf.5.md)**, **[containers-storage.conf(5)](https://github.com/containers/storage/blob/main/docs/containers-storage.conf.5.md)**, **[buildah(1)](https://github.com/containers/buildah/blob/main/docs/buildah.1.md)**, **oci-hooks(5)**, **[containers-policy.json(5)](https://github.com/containers/image/blob/main/docs/containers-policy.json.5.md)**, **[crun(1)](https://github.com/containers/crun/blob/main/crun.1.md)**, **[runc(8)](https://github.com/opencontainers/runc/blob/master/man/runc.8.md)**, **[subuid(5)](https://www.unix.com/man-page/linux/5/subuid)**, **[subgid(5)](https://www.unix.com/man-page/linux/5/subgid)**, **[slirp4netns(1)](https://github.com/rootless-containers/slirp4netns/blob/master/slirp4netns.1.md)**, **[conmon(8)](https://github.com/containers/conmon/blob/main/docs/conmon.8.md)**
 
 ## HISTORY
 Dec 2016, Originally compiled by Dan Walsh <dwalsh@redhat.com>
diff --git a/hack/xref-helpmsgs-manpages b/hack/xref-helpmsgs-manpages
index af54f05f3..6a2d627bb 100755
--- a/hack/xref-helpmsgs-manpages
+++ b/hack/xref-helpmsgs-manpages
@@ -54,6 +54,11 @@ option is listed in the appropriate man page and vice-versa.
 
 $ME invokes '\$PODMAN' (default: $Default_Podman).
 
+In the spirit of shoehorning functionality where it wasn't intended,
+$ME also checks the SEE ALSO section of each man page
+to ensure that references and links are properly formatted
+and valid.
+
 Exit status is zero if no inconsistencies found, one otherwise
 
 OPTIONS:
@@ -286,6 +291,9 @@ sub podman_man {
         elsif ($line =~ /^\#\#\s+(SUB)?COMMANDS/) {
             $section = 'commands';
         }
+        elsif ($line =~ /^\#\#\s+SEE\s+ALSO/) {
+            $section = 'see-also';
+        }
         elsif ($line =~ /^\#\#[^#]/) {
             $section = '';
         }
@@ -340,6 +348,11 @@ sub podman_man {
                 }
             }
         }
+
+        # It's easy to make mistakes in the SEE ALSO elements.
+        elsif ($section eq 'see-also') {
+            _check_seealso_links( "$subpath:$.", $line );
+        }
     }
     close $fh;
 
@@ -427,5 +440,119 @@ sub podman_rst {
 
 # END   data gathering
 ###############################################################################
+# BEGIN sanity checking of SEE ALSO links
+
+##########################
+#  _check_seealso_links  #  Check formatting and link validity.
+##########################
+sub _check_seealso_links {
+    my $path = shift;
+    my $line = shift;
+
+    return if ! $line;
+
+    # Line must be a comma-separated list of man page references, e.g.
+    #    **foo(1)**, **[podman-bar(1)](podman-bar.1.md)**, **[xxx(8)](http...)**
+  TOKEN:
+    for my $token (split /,\s+/, $line) {
+        # Elements must be separated by comma and space. (We don't do further
+        # checks here, so it's possible for the dev to add the space and then
+        # have us fail on the next iteration. I choose not to address that.)
+        if ($token =~ /,/) {
+            warn "$ME: $path: please add space after comma: '$token'\n";
+            ++$Errs;
+            next TOKEN;
+        }
+
+        # Each token must be of the form '**something**'
+        if ($token !~ s/^\*\*(.*)\*\*$/$1/) {
+            if ($token =~ /\*\*/) {
+                warn "$ME: $path: '$token' has asterisks in the wrong place\n";
+            }
+            else {
+                warn "$ME: $path: '$token' should be bracketed by '**'\n";
+            }
+            ++$Errs;
+            next TOKEN;
+        }
+
+        # Is it a markdown link?
+        if ($token =~ /^\[(\S+)\]\((\S+)\)$/) {
+            my ($name, $link) = ($1, $2);
+            if ($name =~ /^(.*)\((\d)\)$/) {
+                my ($base, $section) = ($1, $2);
+                if (-e "$Markdown_Path/$base.$section.md" || -e "$Markdown_Path/links/$base.$section") {
+                    if ($link ne "$base.$section.md") {
+                        warn "$ME: $path: inconsistent link $name -> $link, expected $base.$section.md\n";
+                        ++$Errs;
+                    }
+                }
+                else {
+                    if (! _is_valid_external_link($base, $section, $link)) {
+                        warn "$ME: $path: invalid link $name -> $link\n";
+                        ++$Errs;
+                    }
+                }
+            }
+            else {
+                warn "$ME: $path: could not parse '$name' as 'manpage(N)'\n";
+                ++$Errs;
+            }
+        }
+
+        # Not a markdown link; it must be a plain man reference, e.g. 'foo(5)'
+        elsif ($token =~ m!^(\S+)\((\d+)\)$!) {
+            my ($base, $section) = ($1, $2);
+
+            # Unadorned 'podman-foo(1)' must be a link.
+            if (-e "$Markdown_Path/$base.$section.md" || -e "$Markdown_Path/links/$base.$section") {
+                warn "$ME: $path: '$token' should be '[$token]($base.$section.md)'\n";
+                ++$Errs;
+            }
+
+            # Link to man page foo(5) but without a link. This is not an error
+            # but Ed may sometimes want to see those on a manual test run.
+            warn "$ME: $path: plain '$token' would be so much nicer as a link\n"
+                if $verbose;
+        }
+        else {
+            warn "$ME: $path: invalid token '$token'\n";
+            ++$Errs;
+        }
+    }
+}
+
+#############################
+#  _is_valid_external_link  #  Tries to validate links to external man pages
+#############################
+#
+# This performs no actual fetches, so we can't actually check for 404.
+# All we do is ensure that links conform to standard patterns. This is
+# good for catching things like 'conmon(8)' pointing to a .5 URL, or
+# linking to .md instead of .html.
+#
+# FIXME: we could actually rewrite this so as to offer hints on what to fix.
+# That's a lot of work, and a lot of convoluted code, for questionable ROI.
+#
+sub _is_valid_external_link {
+    my ($base, $section, $link) = @_;
+
+    return 1 if $link =~ m!^https://github\.com/\S+/blob/(main|master)(/.*)?/\Q$base\E\.$section\.md!;
+
+    return 1 if $link =~ m!^https://.*unix\.com/man-page/(linux|redhat)/$section/$base$!;
+    return 1 if $link eq "https://man7\.org/linux/man-pages/man$section/$base\.$section\.html";
+
+    if ($base =~ /systemd/) {
+        return 1 if $link eq "https://www.freedesktop.org/software/systemd/man/$base.html";
+    }
+
+    return;
+}
+
+
+
+
+# END   sanity checking of SEE ALSO links
+###############################################################################
 
 1;