To delete all terms, posts & comments in WordPress

init_wp.sh

#!/bin/bash

# Delete all categories.
wp term list category --field=term_id | xargs wp term delete category

# Delete all post tags.
wp term list post_tag --field=term_id | xargs wp term delete post_tag

# Delete all posts.
wp post delete --force $(wp post list --format=ids)

# Delete all pages.
wp post delete --force $(wp post list --post_type='page' --format=ids)

# Delete all comments.
wp comment delete --force $(wp comment list --format=ids)