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.
QUOTING IN THE SHELL
29 characters named by the standard, 4 ways to take the meaning off them — and the 3 characters where double quotes stop
read: A LINE INTO VARIABLES
The last variable takes the whole rest of the line, inner spaces and all; without -r the backslash disappears, and a line with no final newline gives status 1 — although the variable is already full
INSERTION SORT
the way cards are ordered in the hand · the trace of one real run
QUICKSORT
splitting around a pivot · the trace of one real run
TWO-CAMERA SPEAKER SETUP
the lighting triangle and where each of the 2 cameras stands · the floor plan from above
THREE-CAMERA SPEAKER SETUP
the lighting triangle and where each of the 3 cameras stands · the floor plan from above
THE SELECT STATEMENT
8 clauses in the order you write them — and the order they take effect in
SUBNET MASKS
from /0 to /32: the mask, how many addresses a block holds, and how many of them go to hosts
THE CONDITIONS OF TRAP
FIVE conditions from the standard — EXIT and four signals — and three extensions a conformant shell refuses
THE UMASK
The file mode creation mask: the nine bits it clears, five arguments that name opposite things — and why umask 022 is not chmod 755
UML DIAGRAMS
the fourteen kinds, and the notation a class diagram is made of
THE UNICODE SPACE
1 114 112 code points in 17 planes: 159 866 characters, 137 468 private, 814 730 free