Then delete a line from the file by typing "dd."

but that would be very bad -- because the reader would be prone to type
the string d-d-dot, and it happens that in `vi(1)' dot repeats the last
command accepted. The net result would be to delete *two* lines!

The Jargon File follows hackish usage throughout.

Interestingly, a similar style is now preferred practice in Great
Britain, though the older style (which became established for
typographical reasons having to do with the aesthetics of comma and
quotes in typeset text) is still accepted there. `Hart's Rules' and the
`Oxford Dictionary for Writers and Editors' call the hacker-like style
`new' or `logical' quoting.

Another hacker quirk is a tendency to distinguish between `scare' quotes
and `speech' quotes; that is, to use British-style single quotes for
marking and reserve American-style double quotes for actual reports of
speech or text included from elsewhere. Interestingly, some authorities
describe this as correct general usage, but mainstream American English
has gone to using double-quotes indiscriminately enough that hacker
usage appears marked [and, in fact, I thought this was a personal quirk
of mine until I checked with USENET --- ESR]. One further permutation
that is definitely *not* standard is a hackish tendency to do marking
quotes by using apostrophes (single quotes) in pairs; that is, 'like
this'. This is modelled on string and character literal syntax in some
programming languages (reinforced by the fact that many character-only
terminals display the apostrophe in typewriter style, as a vertical
single quote).