Question

I’m a little confused about the terminology I should use when referring to Linux command line programs and commands.

If I were to execute a command such as:

mkdir testing_dir

Would “testing_dir” be called an ‘operand’ to the program mkdir, or an ‘argument’ or a ‘parameter’?

Another question I have is, what terminology would you use to describe the following process?

find *.txt | grep a | grep b

Could I say; the output of the “find” program is piped (redirected) to the input of the grep program?

Answer 1

For the first question, it is an “argument”. That is why in C programs, the main prototype is int main(int argc, char** argv). argc means argument count, and argv means argument vector.

For the second, it is “piped”. (Because it is done with the pipe | charactor, and/or the data is passed from one program, like it is going through a pipe.) Generally, stdout is only called “redirected” when it is sent to a file with the > operator.