Frontmatter bulk editing

I have a lot of pages in a site generated by a conversion from typo3. Now I want to improve custom settings and taxonomy in the frontmatter of a large subset of these pages.

Do you have any tool suggestion beside sed to batch edit the custom headers? For example I have to move a field from a custom header to taxonomy. Anyone who did similar operations and can give me hints?

Interesting, it's all there, right. Thank you for that. I'am not a php-lover coming from java and unnaturally try to avoid it, but without a real reason. I will read the API pages of the events and the modification calls. Where should I place that code? Would it be in a plugin or elsewhere?

For things related with your site only you can use the theme.php file, that's one possibility, or you prepare a re-usable plugin for your bulk edits to have it at hand in the future. Grav offers good documentation and it's in fact quite easy if you have some basic knowledge.

Thank you very much for your answer, I had a try and success with my first plugin:

    /**
     * When pages are initialized read and modify headers.
     *
     * @param Event $e
     */
    public function onPagesInitialized(Event $e) {
        $debugger = $this->grav['debugger'];

        // Get page
        $page = $this->grav['page'];

        $collection = $page->evaluate(['@page.children' => '/jkirchenkapellen'])->ofType('country');
        foreach ($collection as $cpage) {
            $changed = false;
            if (is_array($cpage->header()->taxonomy['country']) && isset($cpage->header()->taxonomy['country'][0])) {
                $countryKey = $cpage->header()->taxonomy['country'][0];
                $cpage->header()->taxonomy['country'] = $countryKey;
                $changed = true;
                $debugger->addMessage($cpage->header()->taxonomy['country']);
            }
            if ($changed) {
                $cpage->save();
            }
        }
    }

This changes

taxonomy:
    country:
        - austria

to

taxonomy:
    country: austria

😀

Freut mich. Viel Erfolg weiterhin.