Open a MySQL prompt without retyping database credentials by using dbconsole with the password flag, optionally for another Rails environment.

Ruby regular expression support may require the Oniguruma engine and its native libraries before gem install oniguruma succeeds.

Opera 11.10 adds -o-linear-gradient support for CSS3 backgrounds, including angles, multiple color stops, and other CSS color formats.

Encrypted connections between Rails and Amazon RDS MySQL protect sensitive data in transit. mysql and database.yml can be configured to require SSL end to end.

Rails 3.1 asset pipeline issues in production can break precompiling, fingerprinting, and stylesheet rendering when Haml, Sass, and Compass are involved.

ANSI color codes in Rails logs clutter less and vim; stripping escape sequences with sed produces readable log output or a colorless file.

raise_error without an expected exception can pass for unrelated bugs, so matching a specific error class and message makes specs meaningful.

Capybara and Cucumber can assert field validation errors by checking for .field_with_errors around a named form field.

Failed @javascript Cucumber steps can close the Selenium browser before the page state is inspected. Keeping the window open on failure helps debug the created data.

Heredoc strings keep long Ruby text readable while preserving line breaks and interpolation. <<~ removes indentation; <<- and custom delimiters support flexible multi-line literals.

Rotating an Amazon ELB SSL certificate requires IAM server certificate upload and attaching the new ARN to the load balancer listener.

Rails or Rake can report missing gems even when they are installed; wrong Bundler configuration or release-directory leftovers often redirect gem lookup to the wrong place.

Ruby methods can behave like blocks by turning them into callables with Object#method and passing them via & to block-taking methods.

Duplicate line removal in text files can be done with uniq -u, which writes only unique lines to an output file.

Certain regular expressions can take extremely long to match because nested repetition triggers catastrophic backtracking, as in (x+x+)+y.

Remote branch names are useful for pulling, checking out, or merging work from another repository. git branch -r lists remote branches; git branch -a shows all branches.

CSS selectors can target elements by attribute values, enabling styling without extra classes or IDs and useful hooks for forms, links, and data attributes.

Pre-sold requirements with no room to renegotiate create unnecessary complexity and lock clients into needs that change over time.

Set existing files to 0 bytes with truncate -s0; missing files are created, which makes log-file clearing and bulk file reset fast.

selenium-webdriver versions after 2.5.0 can make Capybara fail to choose <select> options even when the option is present, affecting Firefox tests.

rake db:create fails when MySQL access or credentials are wrong, often because the configured user lacks permission to create the development database.

rake can fail with a misleading cannot remove Object::ClassMethods error when a hidden boot-time exception triggers Rails cleanup instead of the real cause.

Homebrew can fail on first install when it cannot access /usr/local directories. Fixing ownership lets brew install run normally.

Solr can start normally yet still return 404 Not Found when its log directory is not writable for the runtime user.