I was trying to search for a way how to use echo with a program I have written in C.
The program takes a word from stdin as input and I would like to know the command that will put whatever I type into echo into my program's input.
I was shown how to do this once but I forgot to write the command down and now I forgot it and cannot find it anywhere.
To use echo, you can do:
echo foo | a.out
Depending on your PATH, you may need to add
echo foo | ./a.out
(This is specifying a relative path to the program to be run, rather than letting the shell find it in PATH)
If you care about whitespace, you'll want to use quotes:
echo 'white space matters' | ./a.out