Creating and Moving Files in the Terminal
Objectives
- How to rename files/folders
- Move files/copy files
- Delete files and folders
- Create files in 2 ways
- Create folders
Creating a file
The touch command creates new empty files. It takes one argument, name or path of the file to be created. Example:
touch ~/Sites/README.md
The above command creates a file called README.md in the Sites folder. You can also create a file in whichever directory you're currently in by running touch myFile.txt.
Another way to make a file
The echo command will output text to the terminal.
It works like this: echo "Some text".
When combined with UNIX concepts like piping and redirecting you can redirect the output of echo into a file like this: echo ".DS_Store" > .gitignore. That command will put the text ".DS_Store" (which is an annoying hidden file OS X puts in folders) into a file called .gitignore. If the file doesn't exist it will be created. If the file had already been full of text, the contents of the file would have been replaced with whatever you passed to echo. To append some text to the end of a file using echo you use a double angle bracket like thic: echo "This will go to the end of an existing file" >> .gitignore.
Moving Files
The mv command will move a file from one place to another. This command can also be used to rename a file. Suppose we have a file called example.txt and we wanted to rename it to be a Markdown filewe would use mv like this:
mv example.txt example.md
If we wanted to move the file somewhere else we would do it like this:
# Method 1 - Moves the file without renaming
mv example.txt ~/Desktop/
# Method 2 - Moves the file and renames it to "sample.txt"
mv example.txt ~/Desktop/sample.txt
Deleting Files
The rm and rmdir commands will remove files and folders respectively.
rm is made for deleting files. When you rm on the command line the file is immediately deleted - it does not go to the Trash first. This command cannot be used on folders. The only exception is deleting a folder and all of its contents recursively. To do this, run this command: rm -rf folder_name_to_delete/
In the above example the -rf flag tells rm to recursively remove the files and folders.
rmdir will remove folders but only if they're empty. If the folder contains files or other folders then you need to use the rm -rf command (the rm command with the rf flag).
echo and Redirection
echo "This bookshelf flexes under the weight of the books it holds" > bookshelf.txt
Using the closing angle bracket > in this way is called redirection. Every command that we run in the shell has an input, an output, an error output, and arguments/operands. We are saying: "Run echo with this string as an operand, and take the output and put it in a new file called bookshelf." Try running ls again, and cat our new file.
Two angle brackets >> appends the string to the end of the file:
Piping
These use the example we used earlier. Try cat books.txt(create it if you haven't), and cat books.txt | sort. The character | is called the pipe. We take the output from cat books.txt and send it through a pipe to sort. The output of cat books.txt becomes the input of sort. Now send the output of sort to a file:
Try This
cat books.txt | sort
Try This
cat books.txt | sort > sorted_books.txt
Try This
cat books.txt | grep Mil
See how we filtered out just the lines that contain Mil? Try grepping for something else.
Try it yourself
- Create a folder named "zoo"
- Now add some animals to your zoo. Create text files for these animals:
- snake.txt
- spider.txt
- spider2.txt
- sloth.txt
- dolphin.txt
- All of these animals can't live together in the zoo. Create folders to categorize the animals as:
- insects
- reptiles
- mammals
- water_animals
- Now put the animals in their correct folder
- Uh oh, the spiders got in a fight or mated or something and one ate the other one. Delete the second, eaten spider