Re: [TUHS] Shell Level...

[markus schnalke <meillo@marmaro.de>]

Hoi.

[2020-01-19 14:22] Grant Taylor via TUHS <tuhs@minnie.tuhs.org>
>
> Have you ever used shell level, $SHLVL, in your weekly ~> daily use of Unix?

What's the use of it? The only use of $SHLVL I can think of is the
answer to the question if ^D will close the last shell or just a
sub shell. I hardly ever ask myself this question. Probably that
starts to become relevant when you open sub shells frequently.


> Someone also mentioned quickly starting a new sub-shell from the current 
> shell for quick transient tasks, i.e. dc / bc, mount / cp / unmount, 
> {,r,s}cp, etc., in an existing terminal window to avoid cluttering that 
> first terminals history with the transient commands.

With tmux or screen at hand, this use case is obsolete for me.
(Besides, my shell doesn't know about $SHLVL.)

This all pretty much depends on your working habits, of course.
For instance, I never use history expansion but search the
history frequently, thus additional entries in the shell history
are no problem. I rather like to have all shell histories merged
into one for having search access to all the commands I executed.
This seems to be more of a modern shell usage concept.

Job control, OTOH, I use a lot, to suspend the editor, grep for
something, resume the editor, and the like. Which seems to be more
of an older style usage concept.


> That got me to wondering if there were other uses for shell level 
> ($SHLVL).  Hence my question.

I'm interested as well, as I've got difficulties imagine these
uses.


One thing to clarify: Are you looking for uses of the shell
variable $SHLVL or for uses of frequent sub shells?


meillo