> my apologies if there's a much easier solution for the following
> problem - in this case please let me know!
We can always define a shell function (which would work in all the
POSIX shells):
read_line() { read line || test -n "$line"; }
printf '%s' "$input" | while read_line; do printf ' %s\n'; done
> [...] (probably relying on undocumented features)
All the POSIX shells (bash, zsh, ksh, dash, etc.) behave in this way
and I think this is the behavior implied by the POSIX standard:
> XBD 3.206
> (https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap03.html#tag_03_206)
> 3.206 Line
> A sequence of zero or more non- <newline> characters plus a terminating
> <newline> character.
>
> XCU 4 read
> (https://pubs.opengroup.org/onlinepubs/9699919799/utilities/read.html)
> NAME
> read - read from standard input into shell variables
> [...]
>
> DESCRIPTION
> The read utility shall read a single logical line from standard input into
> one or more shell variables.
> [...]
>
> EXIT STATUS
> The following exit values shall be returned:
> 0
> Successful completion.
> >0
> End-of-file was detected or an error occurred.
