Two independent shell lists connect through HISTFILE: session A appends with -a, and session B imports with -n.

Bash history is your searchable command log

A useful command history saves retyping, but it is not a complete record of everything executed. Bash normally enables history in interactive shells, and settings can exclude entries or limit retention. The searchable list in a running shell and the history file on disk are separate states. That distinction explains why a command may be visible in one terminal, absent in another, and lost when an unwritten session ends unexpectedly. ...

February 28, 2028 · 5 min · XB Field Notes