Fixed instructions.

_pages/software_instructions.md

@@ -64,17 +64,30 @@ You may contact me directly to obtain the public key fingerprint in a different
 - `project`: the project name
 - `project_python_module`: the python module name of the project.
                            For example: `md-toc` is `md_toc`
-- `tag`: the git tag name which is usually [semver](https://semver.org/)ed
+- `tag`: the git tag name which is usually [semver](https://semver.org/)ed.
+         Get this variable with:
+
+   ```shell
+   git describe
+   ```
+
 - `tag_raw`: same as `tag` but pad each component of the tag with 6 zeros.
              For example: `12.121.5` becomes `000012.000121.000005`
 - `signing_key`: the public key file used to sign the archive file
 - `has_changelog`: the project has a changelog entry for a specific release. Value must be either `true` or `false`
 - `is_on_pypi`: the project is on PyPI. Value must be either `true` or `false`
-- `project_version_release_date`: the release date of a software version.
-                                  This is the command to get the date:
+- `project_version_release_date`: the release date of a software version (tag) in UTC format.
+                                  This is the one liner command to get the date:
+
+  ```shell
+  python3 -c 'from dateutil import parser as dateutil_parser; from dateutil.tz import UTC; import sys; p = dateutil_parser.parse(sys.argv[1]); u=p.astimezone(UTC); print(u.strftime("%Y-%m-%d"))' "$(git tag -l $(git describe) --format='%(taggerdate)')"
+  ```
+
+- `project_version_release_timestamp`: the timestamp of a software version (tag) in UTC format.
+                                       This is the one liner command to get the timestamp:
 
   ```shell
-  git log $(git tag | sort --human-numeric-sort --ignore-leading-blanks | tail --lines=1) -n 1 --date=short --format=%ad
+  python3 -c 'from dateutil import parser as dateutil_parser; from dateutil.tz import UTC; import sys; p = dateutil_parser.parse(sys.argv[1]); u=p.astimezone(UTC); print(u.strftime("%Y-%m-%d %T"))' "$(git tag -l $(git describe) --format='%(taggerdate)')"
   ```
 
 - `changelog_slugified_header`: the slugified header corresponding to a tag in a changelog file
@@ -154,9 +167,8 @@ Add the `### Added`, `### Removed`, etc... contents if applicable.
 In `./_software/CHANGELOG-${project}.md`:
 
 - update the front matter with the appropriate data:
-  - `updated` and `date` must be the UTC representation of the timestamp of the
-    git tag of the last published version
-  - `last_version` must correspond to the git tag used for the last published version
+  - `updated` and `date` must correspond to `${project_version_release_timestamp}`
+  - `last_version` must correspond to `${tag}`
 
 #### Update the table of contents