Click the virtual machine below to start practicing
Your progress through the guide is saved. Start a fresh machine to keep practicing.
Linux doesn't trust file extensions. file looks inside a file and reports what it actually is. Some of the files in ~/project have misleading names.
This lab is the hands-on companion to the file lesson from Linux Journey (CC BY-SA 4.0).
file photo.jpg
photo.jpg: ASCII text
Despite the .jpg, it's plain text.
* matches every name in the directory:
file *
One of these files is really a PNG image. Rename it to real-image.png:
mv <the-image-file> real-image.png
-i prints the MIME type that browsers and mail use; -b (brief) leaves out the filename:
file -i index.html
file -b tool.txt
tool.txt turns out to be a program.
file name reports what a file contains, not what its name suggests.file * checks every file in a directory.-i prints the MIME type; -b omits the filename.