Re: How to replace with `$1` literally?

On Monday, August 8, 2016, Marc Chantreux <[email protected]> wrote:

> On Sun, Aug 07, 2016 at 11:30:04PM -0500, Peng Yu wrote:
> > Hi, The following code is not able to replace ENV with `$1`.
> >
> > /tmp$ m4 -D ENV='$1' <<< ENV
>
> you can add a empty string between $ and 1 to avoid interpolation. to do
> so, your m4 content must be $`'1, not $1.
>
> if your using a shell with rc quoting (rc, es or zsh with rcquotes
> option enabled), you can write:
>
>         m4 -D ENV='$`''1' <<< ENV
>
> the more readable posix way that comes to my mind is
>
>         m4 -D ENV=$\`\'1 <<< ENV


The thing to replace ENV might be read from a file.

m4 -D ENV=$(< file) << ENV

How to escape the content of file so that the content of file will be used
to replace ENV literally?


> regards
>
> marc
>


-- 
Regards,
Peng