Re: Arithmetic expansion with increments and output redirection

[Greg Wooledge]

On Wed, Apr 24, 2019 at 06:47:41AM -0600, Ian Neal wrote:
> At what point is a subshell being invoked? There's no pipeline, command
> substitution, coprocess, background process, or explicit () subshell here,
> which are the only cases a subshell should be created. Otherwise, the
> entire operation should be evaluated by the main shell. Arithmetic
> expansion is not in that list.

The context got snipped but IIRC it was something like

/bin/true > $((n++))

The /bin/true forces the use of an external command, which means a subshell
is forked.  The redirection occurs in the forked subshell.