RSpec 3 argument matching can accept broader values than strict equality, especially for classes, regexps, and ranges. Use eq or a block for exact expectations.

Transactional test fixtures can suppress after_commit callbacks in Rails, preventing email jobs and other post-save work from running. Rails 5 fixes this; older versions can use test_after_commit.

Bulk inserts into one table can be much faster inside a transaction; Rails 6+ also offers insert_all for a single multi-row INSERT without validations.

CI-only workflows can delay local deployments until a commit lands on the branch. A shell alias can wait for the next update and trigger cap staging deploy automatically.

Git diff output uses less, and repeated case-insensitive searches are easier when less -i is configured globally.

Geordi suggests related commands and options after successful runs, surfacing hand-picked hints with a low random probability.

rake --where reveals the source file and line that define a task, useful for tracing where assets:precompile comes from.

Column editing in Vim lets the same change be applied to several lines at one cursor position. Ctrl+v visual block mode and insert mode make repeated edits fast.

Head element order can affect perceived page performance, and Capo helps identify out-of-order elements and suggest a faster arrangement.

Terminal emulators can show unhelpful titles like the shell name instead of the current directory. Bash and Zsh can update the window title automatically with an escape sequence.

Ruby distinguishes explicit and implicit conversion methods; implicit ones like to_hash should only be implemented when an object already behaves like the target type.

Long diffs can hide real edits inside large code moves; git diff --color-moved=dimmed-zebra dims unchanged moved lines and highlights changes.

Shared behavior in traits or modules can be tested once with RSpec shared example groups instead of duplicating specs for each class.

Parallel bundle install speeds up gem installation during development when switching projects often; bundle config jobs sets the number of worker processes.

ss lists open TCP and UDP ports and the processes bound to them, making it easier to find what is listening on a local machine.

Selenium E2E tests can miss frontend JavaScript errors because browser console logs do not fail specs by default. BrowserConsole raises on console errors and supports ignore rules.

Capybara feature specs do not reliably catch server exceptions in another thread; request specs or visible UI assertions fit this user-level behavior better.

Print every Redis key and value to the console for debugging, handling strings, hashes, lists, sets, and sorted sets with a Ruby script.

HTML form usability improves with type, inputmode, enterkeyhint, and autocomplete, giving better mobile keyboards, clearer enter actions, and smarter browser autofill.

Quick reference for byebug debugging commands, breakpoints, stack navigation, variable inspection, and thread control.

Patch-level Ruby updates can break native gems when Bundler shares bundles across 2.6.x versions, leaving failed deploys with incompatible extensions.

Ruby’s special global variables are harder to read and can fail without require 'English', especially in Rails where the library is not loaded by default.

Reduce spaghetti code by splitting behavior into focused functions, service classes, form models, and value objects, while avoiding long parameter lists and excessive DRY.

RubyMine rubymine:// links can fail on GNOME/Linux, blocking better_errors from opening source files in the editor. A custom desktop handler and BETTER_ERRORS_EDITOR_URL make file jumping work.