If a program reads from its standard input, we can use the ``here document'' concept in shell scripts. It is best illustrated with an example. Suppose we have a program p1 that reads two integers followed by a string. We can orchestrate this in our script as follows:
#!/bin/sh p1 <<END 12 22 string1 END
where END is an arbitrary token denoting the end of the input stream to the program p1.