Create Child Theme via CLI

warning

Run this on staging first. A typo in style.css or functions.php can break theme activation or site rendering.

Prerequisites

File/folder	Required	Purpose
generatepress-child/	Yes	Child theme folder under wp-content/themes/
style.css	Yes	Theme header + parent link (Template: generatepress)
functions.php	Yes	Enqueue styles and register hooks/filters
screenshot.png	Optional	Admin thumbnail

Safety Notes

• CLI creation is repeatable and works over SSH.
• You can store the child theme in Git and deploy it like application code.
• A minimal child theme is easier to debug than a pre-bloated starter.

How It Works

WordPress scans wp-content/themes/ for folders with a valid style.css header. The Template: header tells WordPress which parent theme to inherit from.

flowchart LR
  STYLE[style.css header] --> WP[WordPress theme registry]
  WP --> PARENT[Parent: generatepress]
  WP --> CHILD[Child: generatepress-child]

Step-by-Step Creation

Step 1: Create the Theme Folder

create-child-theme-folder.sh

cd /var/www/html
mkdir -p wp-content/themes/generatepress-child
ls -lah wp-content/themes | grep generatepress

Step 2: Write style.css (Minimum Header)

write-style-css.sh

cat > wp-content/themes/generatepress-child/style.css <<'EOF'
/*
Theme Name: GeneratePress Child
Template: generatepress
Version: 0.1.0
Text Domain: generatepress-child
*/
EOF

Step 3: Write functions.php (Enqueue Parent + Child)

write-functions-php.sh

cat > wp-content/themes/generatepress-child/functions.php <<'EOF'
<?php

add_action( 'wp_enqueue_scripts', function() {
    wp_enqueue_style(
        'generatepress-parent',
        get_template_directory_uri() . '/style.css'
    );

    wp_enqueue_style(
        'generatepress-child',
        get_stylesheet_directory_uri() . '/style.css',
        array( 'generatepress-parent' ),
        filemtime( get_stylesheet_directory() . '/style.css' )
    );
} );
EOF

Step 4: Activate the Child Theme

activate-child-theme.sh

cd /var/www/html
wp theme activate generatepress-child
wp option get stylesheet
wp option get template

Expected output:

generatepress-child
generatepress

Step 5: Verify the Parent Link

verify-template-header.sh

cd /var/www/html
grep -n "^Template:" wp-content/themes/generatepress-child/style.css

Expected output:

Template: generatepress

Optional Configuration

Example 1: Roll Back to Parent Theme (Emergency Command)

rollback-to-parent.sh

cd /var/www/html
wp theme activate generatepress
wp option get stylesheet

Example 2: Package the Child Theme as an Artifact

package-child-theme.sh

cd /var/www/html
tar -czf /tmp/generatepress-child.tgz -C wp-content/themes generatepress-child
ls -lh /tmp/generatepress-child.tgz

Best Practices

Practice	Why
Start minimal, then add structure	Easier to debug
Use filemtime() for cache-busting in staging	Prevents stale CSS
Keep theme name and folder name stable	Avoids deploy mismatches
Commit early to Git	Rollback and audit trail

Troubleshooting

Symptom	Cause	Fix
Theme not listed	Missing Theme Name: header	Fix style.css header and re-check
Activation fails	Wrong folder name	Ensure folder is generatepress-child
No styles	Parent not enqueued	Confirm enqueue code in functions.php
White screen	PHP syntax error	Check /usr/local/lsws/logs/error.log

Hands-On

1. Create the child theme via CLI.
2. Activate it and confirm stylesheet and template values.
3. Package it to /tmp/generatepress-child.tgz.

Quick Reference

child-theme-cli-cheatsheet.sh

cd /var/www/html
mkdir -p wp-content/themes/generatepress-child
wp theme activate generatepress-child
wp option get stylesheet

What's Next

• Next: style.css Header & Metadata
• Related: Child Theme Setup (overview)