Re: Call a function when idle?

[Mikael Magnusson <mikachu@gmail.com>]

On 12/14/20, A. Wik <awik32@gmail.com> wrote:
> Hi all,
>
> For the most part, when I get started working at a terminal, I can do
> just fine with a simple and short prompt like "% ".  A prompt that
> includes the current directory often gets annoyingly long so that you
> can rarely type a command line that doesn't scroll onto another line,
> which is harder to read.
>
> However, when I've been away from a terminal (window or tab) for some
> time, I would like to know where in the file system I am, to remind me
> (hopefully) of what I was doing.  If the current working directory is
> not in the prompt, I have to type "pwd" manually.
>
> To solve the problem, I was thinking of getting a function to run
> after a specified period of idle time.  This function could then run
> "print -P" to print useful pieces of data, such as the hostname, the
> tty name, etc., and of course the current directory.
>
> So, the question is how to set up an idle timer to call the function.
> I figured someone had already done something like that before (perhaps
> to log out automatically).

TMOUT  If  this  parameter  is  nonzero, the shell will receive an ALRM
       signal if a command is not entered within the  specified  number
       of  seconds  after  issuing  a  prompt.  If  there  is a trap on
       SIGALRM, it will be executed and a new alarm is scheduled  using
       the  value  of the TMOUT parameter after executing the trap.  If
       no trap is set, and the idle time of the terminal  is  not  less
       than  the  value of the TMOUT parameter, zsh terminates.  Other‐
       wise a new alarm is scheduled to TMOUT seconds  after  the  last
       keypress.

You may want to unset TMOUT in your handler and then arrange for it to
be set when you enter a new command line and/or any relevant
information has changed, otherwise you will come back to a lot of the
same information. And/or use zle -M to print the information, it will
be printed below the prompt (replacing any previous such message), it
will then be lost when overwritten by further commands/prompts. eg,

zle -N zle-line-init _zle_line_init
function _zle_line_init() {
  TMOUT=3
}
TMOUT=3
TRAPALRM() { zle -M "hi there, you're in $PWD"; unset TMOUT }

-- 
Mikael Magnusson