Steps For Installing PHP Composer on Ubuntu STEP 1: Update You distribution Enter this command to update the local repository lists. STEP 2: Download the Composer Installer run the below command in your root directory (We are installing composer globally) Step 3: Verify Integrity of the Download 1. Visit the Composer Public Keys page. Copy the Installer Signature (SHA-384).2. Set the code shell variable: COMPOSER=48e3236262b34d30969dca3c37281b3b4bbe3221bda826ac6a9a62d6444cdb0dcd0615698a5cbe587c3f0fe57a54d8f53. Run the script below to compare the official hash against the one you downloaded: Step 4: Install