How to input a read value when calling a shell script

Question

Let say I have this line in a shell script in unix:

read -n 1

It will prompt the user to get value but is there a way to call the script so it takes the input as argument instead?

Like this for example:

myscript.sh "M"

I want to call the script from a build engine so it cannot answer with keyboard input.

Answer 1

To use argument values in shell script you can pass the argument with the script and then refer them using $1, $2, $3 and so on.

Answer 2

You can use Here Strings in bash:

myscript.sh <<< "M"

Or use pipeline:

echo "M" | myscript.sh

Here string documentation

Answer 3

Use this with some frequency:

hello() {  read -n1 CHAR;  echo $CHAR; }
echo world | hello

Answer 4

How about

myscript.sh $(read -n 1)

?