Today I learned

My “today I learned” snippets. Inspired by Simon Willison.

git

• git add takes an --update flag
• git ignores aliases that shadow existing commands

github

• Links in GitHub readmes need percent encoding

javascript

• JavaScript's Date constructor is picky with ISO dates

mac

• You can hide preference panes in System Preferences

python

• pytest parameterized test cases can have custom descriptions

shell

• How to call xargs with each argument in turn
• How to wrap bc to do calculations

sql

• Postgres check constraint names can contain spaces