Charts for people who write code
These are not tutorials. They are the things you know perfectly well and still look up: which redirect preserves the method, what flex: 1 actually expands to, whether a change is in the working tree or the index, how many bytes someone means by a gigabyte.
HTTP status codes are grouped by class rather than listed in numeric order, because that is how they are reasoned about. Flexbox is split into what belongs on the container and what belongs on the item — the distinction people actually get wrong. The Git sheet draws the places a change can be sitting between your editor and the remote. And the data units sheet runs from the bit upwards, where the same word keeps meaning two different numbers.
They belong on the wall of a study or a small office: the kind of reference you glance at without breaking a train of thought to open a browser tab.
THE EXIT STATUS
One byte from a command to the shell: what the standard assigns in it, what it leaves to the system — and why “128 + signal number” is nowhere in the standard
FILE DESCRIPTORS
Three levels between a number and a file: what two numbers of one description share, what two descriptions do not — and where the offset lives
FILE LOCKS
A lock lies on a range of bytes, it has two different kinds of owner, and it guards no byte at all
FILE PERMISSIONS
Nine bits in three triads, three special bits — and why r and x on a directory are different powers
CSS FLEXBOX
main axis and cross axis · which property belongs to which
A NUMBER IN 32 BITS
sign, exponent and significand: what actually sits in a float and what does not
FLOWCHART SYMBOLS
10 shapes, and one algorithm drawn with them
GIT WORKING AREAS
four areas · the command that moves code between them
FILENAME EXPANSION: *, ?, […]
A leading dot and a slash disappear only in filename expansion: the same pattern “*” is seen by case, but not by expansion itself
GO vs RUST
seven questions, the same to both, and the document each answer is written in
HERE-DOCUMENTS
The body reaches the command as a single word, and one quote in the delimiter decides whether it arrives as typed
HTTP METHODS · 2026
ten methods per RFC 9110, 5789 and 10008: which are safe, which are idempotent, which can be retried