Two interactive Bash sessions are open with normal settings.
A command just run in one session is not yet present when the other rereads ~/.bash_history.
Which general explanation is appropriate?
Each Bash keeps a session history list and normally writes it to HISTFILE at exit or another configured time, so two sessions can temporarily differ.
Detailed explanation
Correct. The in-memory history and on-disk HISTFILE can be out of sync until a write occurs.
Correct. The in-memory history and on-disk HISTFILE can be out of sync until a write occurs.
Incorrect. ~/.bash_history is normally a readable text file, not an executable.
Incorrect. ~/.bash_history is normally a readable text file, not an executable.
Incorrect. Each Bash process has its own history list rather than one shared list.
Incorrect. Each Bash process has its own history list rather than one shared list.
Incorrect. The history file stores command lines, not only environment variables.
Incorrect. The history file stores command lines, not only environment variables.
Try it yourself
An example you can run in a temporary verification environment.
bash -c 'printf "HISTFILE=%s\n" "${HISTFILE:-not-set-in-noninteractive-shell}"'Expected result
非対話シェルでは未設定の場合もあることを示す表示Key points
- Session history and the file differ
- The default HISTFILE is ~/.bash_history
- Write timing creates a delay
Notes
- Environment: Bash 5.x / 説明確認のみ
- Command output formatting can vary slightly by distribution or tool version.
- Run the example in a temporary directory or process when possible.
Foundation review
Read the scope first
Check whether the command acts on the current shell, a new process, an existing process, or a file.
Verify the observable result
Use the supplied command and compare the output with the expected result.