In this section, we'll create a text file that we can use as a cheat sheet. You can use it to keep track of all the awesome commands you're learning.
Instead of creating an empty file like we did with touch, let's try creating a file with some text in it. But first, let's learn a new command: echo
$ echo "Hello from the command line"
Hello from the command line
By default, the echo command just prints out the text we give it. Let's use it to create a file with some text in it:
echo "This is my cheat sheet" > cheat-sheet.txt
Now let's check the contents of the directory:
$ pwd
/Users/jojo/projects
$ ls
cheat-sheet.txt
OK, so the file has been created. But what was the > in the command we used? On the command line, a > is known as a "redirect." It takes the output of a command and puts it in a file. Be careful, since it's possible to overwrite files with the > command.
Let's check if there's any text in cheat-sheet.txt.
cat cheat-sheet.txt
This is my cheat sheet
As you can see, the cat command prints the contents of a file to the screen.
Your cheat sheet is titled cheat-sheet.txt instead of cheat sheet.txt for a reason. Can you guess why?
Try to make a file titled cheat sheet.txt and report to the class what happens.
Now imagine you're attempting to open a very important data file using the command line that is titled cheat sheet.txt.
For your digital best practices, we recommend making sure that file names contain no spaces--you can use creative capitalization, dashes, or underscores instead.
The challenge for this section will be using a text editor to add some of the commands that we've learned to the newly created cheat sheet. Text editors are programs that allow you to edit plain text files, such as .txt, .py (Python scripts), and .csv (spreadsheet files). Remember not to use programs such as Microsoft Word to edit text files, since they add invisible characters that can cause problems. During the Institute, we'll be using Sublime as our text editor.
Open Sublime Text and select File > Open file from the menu bar. Add the commands we've learned so far to the file. Include descriptions about what each command does. When you're done, save the file by selecting File > Save from the menu bar.
Once you're done, check the contents of the file on the command line with the cat command:
$ cat cheat-sheet.txt
My Institute Cheat Sheet
ls
lists files and folders in a directory
cd ~
change directory to home folder
...
