THREE HAND STITCHES
backstitch · running stitch · whipstitch — what shows on the face and what the thread does underneath
STAIN REMOVAL
five stain classes and the method for each — per publication H.E. 2-840 of the University of Kentucky Cooperative Extension
BINARY COUNTING
five doubling cards build every number from 0 to 31 — exactly the way every computer counts
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
GIT WORKING AREAS
four areas · the command that moves code between them
LOGIC GATES
Seven digital-logic symbols — and how to build six of them from a single element, NAND
THE FLAGS OF OPEN()
FIVE flags of creating a file — and why O_CREAT|O_EXCL is not a faster check but a check and a creation joined into one indivisible act
${…}: TRIMMING BY PATTERN
The sign says from which end to cut and doubling it says how much: from the same path the same pair of patterns takes away either one character or fifteen
THE ORDER OF REDIRECTIONS
Redirections are done from left to right, and “2>&1” copies where the output points at that very moment: the file first — and it holds two lines; the copy first — one
THE CONDITIONS OF TRAP
FIVE conditions from the standard — EXIT and four signals — and three extensions a conformant shell refuses
FIRST FINGER FOODS
the size, the softness and the shape of a piece for a baby who feeds themselves, by the NHS guidance
NEAPOLITAN PIZZA DOUGH
four ingredients in the proportions written into an EU regulation