[Help-bash] Is there a construct in bash that can replace cat?

[Peng Yu]

Hi,

I have the following toy script. Depending the option totext, I want
to filter the input to text or to just pass the input to the output
without changing anything. For the latter case, I use cat. But this
involves calling the external program cat. Is there a way to do it in
bash internally without resorting to an external program? Thanks.

~$ cat main.sh
#!/usr/bin/env bash

totext=x

function filter {
if [ "$totext" ]
then
  col -b
else
  cat
fi
}

some_program | filter

-- 
Regards,
Peng