Re: Read the input as a whole

[Ed Morton]

The first (with `RS=""`) will read the first paragraph in the file, not 
the whole file unless that file contains no blank lines.

The second (with `RS="^$") will read the whole file but only with gawk 
or another awk that supports multi-char RS. With a POSIX awk it'll treat 
it as if you wrote `RS="^"` and only read the first `^`-separated record.

    Ed.

On 6/11/2021 9:06 AM, Peng Yu wrote:
> Hi,
>
> Both of the following commands can read a whole input. Are they always
> the same under all possible input? Is there one preferred over the
> other?
>
> $ builtin printf '%s\n%s' abc 123 | awk.sh -e 'BEGIN { RS=""; getline;
> print $0 }'
> abc
> 123
> $ builtin printf '%s\n%s\n' abc 123 | awk.sh -e 'BEGIN { RS="^$";
> getline; print $0 }'
> abc
> 123