script for reading file or stream

I often wanted to pass the file to a pipeline some command, and also if the file is parameter to command it should accept


Voila!!

here is 'stream.sh'

#!/bin/bash

file=${1:--}

cat $file 

Usage and output

$ ./stream.sh underSTANDING.txt 

If you understand, say "understand".

If you don't understand, say "don't understand".

But if you understand and say "don't understand".

How do I understand that you understand? Understand!

$ cat underSTANDING.txt | ./stream.sh 

If you understand, say "understand".

If you don't understand, say "don't understand".

But if you understand and say "don't understand".

How do I understand that you understand? Understand!

$ ./stream.sh < underSTANDING.txt 

If you understand, say "understand".

If you don't understand, say "don't understand".

But if you understand and say "don't understand".

How do I understand that you understand? Understand!