Re: $(<file) requotes the quotes?

[Paul Jarc]

For help with writing scripts, go to news:comp.unix.shell.

Phil Edwards <phil@jaj.com> wrote:
> Since I can't use 'read' in a loop,

I bet you can, if you do it right.

> I am instead accumulating strings in a temporary file.  The strings
> are "-e" commands that will eventually be fed to sed(1).

Maybe you'd like sed -f.

>     sed -e 'required stuff'                                     \
>         -e 'more required stuff'                                \
>         ...
>         -e 'more required stuff'                                \
>         $(</temporary/file/with/accumulated/optional/stuff)     \
>         input_file > output_file
>
> But sed chokes, because the single-quote characters in the file are being
> quoted and backslash-escaped all over the place.

More precisely, quoting and quote removal are not applied to the
result of the $() expansion; only word splitting is.  This is correct,
documented behavior.

> I thought $(<file) was supposed to be the same as $(cat file),

It is.

> and I'm certain that cat(1) doesn't do that.

Nor does $(<file).  It's a matter of what *isn't* being done, which
normally is done (by bash) for text that is part of the script itself.
You would see the same behavior with cat.


paul