composer require monolog/monolog

    ./composer.json has been created
    Loading composer repositories with package information
    Updating dependencies (including require-dev)
    Package operations: 2 installs, 0 updates, 0 removals
      - Installing psr/log (1.0.2): Loading from cache
      - Installing monolog/monolog (1.23.0): Loading from cache
    monolog/monolog suggests installing aws/aws-sdk-php (Allow sending log messages to AWS services like DynamoDB)
    monolog/monolog suggests installing doctrine/couchdb (Allow sending log messages to a CouchDB server)
    monolog/monolog suggests installing ext-amqp (Allow sending log messages to an AMQP server (1.0+ required))
    monolog/monolog suggests installing ext-mongo (Allow sending log messages to a MongoDB server)
    monolog/monolog suggests installing graylog2/gelf-php (Allow sending log messages to a GrayLog2 server)
    monolog/monolog suggests installing mongodb/mongodb (Allow sending log messages to a MongoDB server via PHP Driver)
    monolog/monolog suggests installing php-amqplib/php-amqplib (Allow sending log messages to an AMQP server using php-amqplib)
    monolog/monolog suggests installing php-console/php-console (Allow sending log messages to Google Chrome)
    monolog/monolog suggests installing rollbar/rollbar (Allow sending log messages to Rollbar)
    monolog/monolog suggests installing ruflin/elastica (Allow sending log messages to an Elastic Search server)
    monolog/monolog suggests installing sentry/sentry (Allow sending log messages to a Sentry server)
    Writing lock file
    Generating autoload files

composer require guzzlehttp/guzzle

    Using version ^6.3 for guzzlehttp/guzzle
    ./composer.json has been updated
    Loading composer repositories with package information
    Updating dependencies (including require-dev)
    Package operations: 4 installs, 0 updates, 0 removals
      - Installing guzzlehttp/promises (v1.3.1): Downloading (100%)         
      - Installing psr/http-message (1.0.1): Downloading (100%)         
      - Installing guzzlehttp/psr7 (1.4.2): Downloading (100%)         
      - Installing guzzlehttp/guzzle (6.3.3): Downloading (100%)         
    Writing lock file
    Generating autoload files