/dev/stdin with herestring

Question

I would like a Bash script that can take input from a file or stdin, much like grep, for example

$ cat          


        

Answer 1

$ cat ts.sh 
read b < "${1-/dev/stdin}"
echo $b

$ ./ts.sh <<< 'hello world'
hello world

No problem for me. I'm using bash 4.2.42 on Mac OS X.