${…}: 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

Built as a memo rather than a table: the thing worth hanging it up for reads across the room, with the full reference in smaller type below it.

Three sizes in one archive — from a sheet on the fridge to a poster on the wall.

Formats: A4 · A3 · A2
What you get: Print-ready PDFs, one per size, with every letterform converted to outlines — nothing to install, nothing to shift.
Subject: code · everyone · memo · study

Read from top to bottom: how many characters each of the four forms removes, what four answers one name gives, and what the fine print costs. Everything was printed by /bin/sh.

THE PATTERN HERE IS NOT A REGULAR EXPRESSION

The standard says it plainly: “pattern matching notation …, rather than regular expression notation, shall be used to evaluate the patterns”. So the dot in the pattern “.*” is a dot, not “any character”: “${v%%.*}” removes seven characters from the first dot, not all twenty eight.

And the asterisk here crosses a slash: the rule about the slash is written for filename expansion — “the following rules that apply when pattern matching notation is used for filename expansion”. That is why “${v##*/}” gives the file name, taking four slashes away with the rest.

On the sheet

Read from top to bottom: how many characters each of the four forms removes, what four answers one name gives, and what the fine print costs. Everything was printed by /bin/sh.
Colour carries meaning, but meaning never rests on colour alone — the sheet reads in black and white.
Nothing about how it was made: the sheet carries only what the reader needs.

Printing

Three sizes in the archive: A4 — 210×297 mm, A3 — 297×420 mm, A2 — 420×594 mm.
All text is converted to outlines. No fonts to install, and nothing shifts on another machine.
White background and sparing fills — it prints on a home printer without draining the cartridge.
Margins of at least 10 mm: a home printer cannot print to the edge.
No stroke thinner than 0.3 mm, so nothing disappears in print.

Why the numbers can be trusted. Every countable number here is computed from data rather than typed in, and the sheet must pass 11 independent checks before it is allowed to build — how many items there are, the order they come in, and the claim in the highlighted box itself. If one fails, there is no file.

${…}: TRIMMING BY PATTERN

THE PATTERN HERE IS NOT A REGULAR EXPRESSION

On the sheet

Printing

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