In Chapter 1, the shell split your line into words, and the first word was the command. Now you will use the other words.

The words after the command

The words after the command are arguments. The shell gives them to the program.

echo writes its arguments, with one space between them:

learner@tidepool:~$ echo deploy finished
deploy finished

The shell removes the extra spaces

The shell splits the line at the spaces. The spaces are not part of the arguments. More spaces between two words give the same two arguments:

learner@tidepool:~$ echo deploy       finished
deploy finished

The next lesson shows how to keep the spaces.

Each program decides what its arguments mean

cat writes the text that is in a file. Its arguments are the names of the files to read:

learner@tidepool:~$ cat notes.txt
deploy started
build ok
deploy finished

Give cat two file names, and it writes the two files, one after the other.