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: *, ?, […]](/api/img/cmsp2eg3h001q2dpdnyxkt8mu)
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