[Toybox] Endless bash questions...

[Chet Ramey]

On 6/4/22 6:08 PM, Rob Landley wrote:
> Why does this work:
> 
> $ [[ $(cat) == "a b" ]] <<< "a b" > potato && rm potato && echo yes
> yes

Here-strings are redirections, and a redirection may follow a compound
command.

> But this is an error?
> 
> $ [[ $(cat) == "a b" ]] <(echo a b) > potato && rm potato && echo yes
> bash: syntax error near unexpected token `<(echo a b)'

Process substitution is a word expansion, and so words consisting only of
process substitutions are words, and words may not follow a compound
command.

> It actually seems to exclude <(subcommands) from all trailing blocks?

Anywhere a word is not allowed.

> $ if true; then cat; fi <(echo hello)
> bash: syntax error near unexpected token `<(echo hello)'

Like here.

> 
> Maybe it's related to restartability?
> 
> $ a() { cat; } <<< potatosalad
> $ a
> potatosalad
> $ a
> potatosalad
> $ a() { cat; } <(echo hello)
> bash: syntax error near unexpected token `<(echo hello)'

And here.

Chet

-- 
``The lyf so short, the craft so long to lerne.'' - Chaucer
		 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU    chet at case.edu    http://tiswww.cwru.edu/~chet/