wp cli media commands not working

Question

I am trying to bulk update media file captions through WP CLI so i can attribute image creators.

My command is as follows:

wp media list --date="2022-02-24" --format=ids | xargs -n 1 wp media meta update {} _wp_attachment_image_alt "<a href='https://www.freepik.com/'>Image by pch.vector on Freepik</a>"

I get these errors:

Error: 'list' is not a registered subcommand of 'media'. See 'wp help media' for available subcommands. Error: 'meta' is not a registered subcommand of 'media'. See 'wp help media' for available subcommands

I have the latest version, 2.7.1

On the WP CLI documentation, it lists media subcommands. There doesn't seem to be any subcommands for updating media meta.

https://developer.wordpress.org/cli/commands/media/

Does this mean there isnt a capability of updating media meta through wp cli?

Answer 1

Media is the post type (post_type="attachment"), so most operations are done with wp post command.

By default, wp post manage blog posts (post_type="post"), therefore by fetching post IDs you must add --post_type=attachment indicating the type of posts.
And to update media meta you should use wp post meta update <id> <key> <value>

Your entire command could look like this:

wp post list --date="2022-02-24" --format=ids --post_type=attachment | xargs -n 1 -I % wp post meta update % _wp_attachment_image_alt "{some meta value}"