02 Navigating Files and Directories - ryandkuster/EPP_575_RNA_25 GitHub Wiki

The part of the operating system responsible for managing files and directories is called the file system. It organizes our data into files, which hold information, and directories (also called ‘folders’), which hold files or other directories.

Let's investigate some directories and files on our personal computers. Open up your terminal and run the command pwd (aka 'print working directory').

Input:

pwd

Output:

/Users/<your_username>

Your home directory path may look different from mine. On Linux/Mac, the home directory will be /home/<username> with forward slashes. The home directory path on Windows will be C:\Users\<username>, separated by backward slashes.

Let's see the contents of our current directory (/home/<username>):

ls -F

The -F is an option or a flag, which tells ls to provide additional classifiers to files and directories.

• Directories will have a trailing /
• Links will have a @
• Executables (scripts) will have an *

Commands like ls have many different options users can utilize - depending on your environment, you can either:

1. Pass --help to any command

ls --help

2. Print the manual with man:

man ls

3. Google!

You can use ls to print a directory's contents without toggling into it. Let's say we want to view the contents of Desktop:

ls -F Desktop

The shell-lesson-data directory should be nestled within your home directory. Let's print the contents of shell-lesson-data to get a peek at what's in there.

ls -F shell-lesson-data

Within shell-lesson-data, we see a directory called exercise-data. Let's toggle into this directory with the command cd (aka 'change directory').

cd ~/command_line_practice/shell-lesson-data/exercise-data

You can go back directories by using .. (which denotes the parent directory):

Use pwd to check current directory. Go back one directory:

cd ..

Go back two directories:

cd ../..

Instead of using the .. notation, we can also use relative (partial) and absolute (full) paths. Let's say we want to cd into the alkanes directory (a sub-directory of exercise-data)

Relative path (starting point is the current directory Desktop):

cd ~/command_line_practice/shell-lesson-data/exercise-data/alkanes

Absolute path (entire path from the root directory, indicated by a leading slash):

cd /Users/<username>/command_line_practice/shell-lesson-data/exercise-data/alkanes

If you want to change into your home directory, you can use a ~:

cd ~

If you want to change to the root directory (the directory that holds everything), you can use /:

cd /

Change back to the shell-lesson-data directory (use pwd to verify). Let's use ls to view the north-pacific-gyre directory.

ls -F north-pacific-gyre

We see that this directory contains a bunch of text files, many of which are sample names that all start with 'NENE'.