What happens when we run
ls? This isn't a trick question.
$ ls -F
Desktop/ Documents/ Downloads/ Music/ Pictures/ Public/ Templates/ Videos/
We get a list of the files and folders in the current directory printed to the screen. But what if we didn't want it to print to the screen but instead wanted to save it to a file somewhere?
By default, commands run on the command line print to
output). If we want to specify a different location to print to, we use the
Try it out:
$ ls -F > filelist
No output appeared on the screen (
stdout). Let's check what's in
$ nano filelist
There it is!
Now, what do we do with it...? How about we try counting the number of lines in
Imagine we have a MUCH bigger directory and we want to know how many files and
folders are in it. When we redirect
ls to a file, every file and folder is
written to a separate line; if we count the number of lines, we know how many
files there are!
How do we count the number of lines? We use
Yes, it's word_count, but it counts lines, words and characters. We'll
wc more later, but for now, let's just count the number of lines in
filelist. To specify that we want the number of _lines in a file we use the
$ wc -l filelist
wc tells us that
filelist has 8 lines, which means we have 8
files/folders in the HOME directory. (Yes, we already knew that since we can
count, but still...)