Re: Rationale for aligning data on even bytes in a Unix shell file?

On 2025-04-26, Janis Papanagnou <janis_papanagnou+ng@hotmail.com> wrote:

In a "C" file (of the Kornshell software) I stumbled across this
comment: "Each command in the history file starts on an even byte
and is null-terminated."

The full(er) text is:

  Each command in the history file starts on an even byte and is
  null-terminated.  The first byte must contain the special character
  HIST_UNDO and the second byte is the version number.

If the file is snarfed into a buffer, then if each command starts
on an even byte, those two-byte pairs will be aligned and can be
accessed as two-byte integers.

At a glance, I don't see where the code relies on that, but maybe
historically it did.

The alignment could be of help if you're looking at the file
with "od -tx2a".

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