Re: [PATCHv2] [bug] $SHLVL decremented for the last command of a subshell

[Stephane Chazelas <stephane.chazelas@xxxxxxxxx>]

2016-08-30 14:04:57 +0100, Peter Stephenson:
[...]
> This is probably fine.  I've been dithering over cases where for
> consistency we might want to decrement SHLVL even in a subshell because
> we're exec'ing for some other reason (so would need to do it at the last
> minute before exiting if the exec is faked), but I suspect this is too
> obscure to be worth special treatment.
[...]

Note that zsh is currently correctly decrementing in

zsh -c '(printenv SHLVL)'

Where zsh optimises out the fork(s).

ksh93 seems to never decrease $SHLVL even in:

$ env SHLVL=1 ksh93 -c 'exec printenv SHLVL'
2

bash only optimises out the fork in the

bash -c 'single command'

case and gets it wrong:

$ env SHLVL=1  bash -c 'printenv SHLVL'
2
$ env SHLVL=1  bash -c 'exec printenv SHLVL'
1

tcsh doesn't opimise out any fork AFAICT.

Other shells don't seem to support $SHLVL.

-- 
Stephane