Filesystem Navigation

The file structure you see in the Terminal is the same as the one you see in the Finder application. Finder tends to hide some of the folders from you to keep things simple for most users, but everywhere that you go in Finder is accessible through the Terminal.

Common Navigation Commands

• pwd - print working directory

• open - open a file/directory

• ls - list directory contents

• cd - change directory

pwd - Where am I?

Wherever we are, pwd (short for print working directory) will show us what directory we are in.

pwd

/Users/romebell

Typically the terminal will start in your HOME directory, each user has their own HOME directory, but on your computer it is common for you to be the only real user. At any given time a terminal shell process has one current working directory

open - Open a file/directory

open .

Wherever we are, open . opens a Finder window in the current directory. This can be handy for going between the terminal and Finder interfaces.

Additionally, we can open a file using the default application for the file.

open index.html

ls - Listing directory contents

We can also list the files and directories in the current working directory. Your list may vary from the files/directories below.

ls

  Applications   Pictures  gitshell.sh rorshell.sh
  Desktop   Library   Public    hashes  rorshellws.sh
  Documents Movies    bin   helloroom work
  Downloads Music   git_profile.sh  phpshell.sh

Listing in the long format

To display this list in a cleaner format, we can pass options to the command. For example, the l option displays the list in a long format.

ls -l

total 10
drwxr-xr-x    2 romebell  staff    68 Dec  4 15:13 Applications
drwx------+   6 romebell  staff   204 Mar 23 18:20 Desktop
drwx------+  11 romebell  staff   374 Feb 27 10:57 Documents
drwx------+ 141 romebell  staff  4794 Apr  5 08:04 Downloads
drwx------@  56 romebell  staff  1904 Apr  4 21:58 Library
drwx------+   3 romebell  staff   102 Nov  4 10:49 Movies
drwx------+   8 romebell  staff   272 Mar  5 15:48 Music
drwx------+  20 romebell  staff   680 Mar 23 12:53 Pictures
drwxr-xr-x+   5 romebell  staff   170 Nov  4 10:49 Public
-rwxr-xr-x    1 romebell  staff   184 Nov  8 16:41 git_profile.sh

Now we can clearly see what files are in the current working directory. Some of these items are files, some are directories.

The ls command can take a directory as an argument

ls -l Documents/

total 3
drwxr-xr-x   4 romebell  staff      136 Feb 22 20:01 Rails
-rw-r--r--@  1 romebell  staff  8154896 Feb 27 10:57 Profile.png
-rw-r--r--@  1 romebell  staff  6258658 Feb 27 10:57 Profile2.png

Listing hidden files

There's also a flag to list hidden files, which are files preceded with a period. These files are normally not visible in the command line unless we explicitly want them.

Using the a flag with ls will list hidden files. Note we can use flags in combination.

ls -la

total 17
  drwxr-xr-x+  76 romebell  staff   2584 Apr  6 10:30 .
  drwxr-xr-x    6 romebell  admin    204 Nov  4 10:47 ..
  -rw-r--r--@   1 romebell  staff  15364 Apr  2 16:00 .DS_Store
  -rw-------    1 romebell  staff   8949 Apr  1 17:21 .bash_history
  -rw-r--r--    1 romebell  staff    285 Mar 17 14:50 .bash_profile
  -rw-r--r--    1 romebell  staff     59 Feb  2 13:47 .bashrc
  drwxr-xr-x    5 romebell  staff    170 Dec  5 13:21 .bundler
  -rw-r--r--    1 romebell  staff    379 Mar  3 17:36 .gitconfig
  drwxr-xr-x   30 romebell  staff   1020 Feb  2 13:47 .rvm
  drwxr-xr-x    2 romebell  staff     68 Dec  4 15:13 Applications
  drwx------+   6 romebell  staff    204 Mar 23 18:20 Desktop
  drwx------+  11 romebell  staff    374 Feb 27 10:57 Documents
  drwx------+ 141 romebell  staff   4794 Apr  5 08:04 Downloads
  drwx------@  56 romebell  staff   1904 Apr  4 21:58 Library
  drwx------+   3 romebell  staff    102 Nov  4 10:49 Movies
  drwx------+   8 romebell  staff    272 Mar  5 15:48 Music
  drwx------+  20 romebell  staff    680 Mar 23 12:53 Pictures
  drwxr-xr-x+   5 romebell  staff    170 Nov  4 10:49 Public
  -rwxr-xr-x    1 romebell  staff    184 Nov  8 16:41 git_profile.sh

Hidden Files are typically used by applications to store configurations and there will be many of them in your home directory. Most users don't want to be editing these files so they don't show up in Finder, but you as a software developer will be editing some these for yourself.

Extra: The columns from the output of ls -la represent (from left to right)

• type (d denotes a directory)

• file permissions

• number of links (contained files and folders)

• owner

• group

• file size

• last modified data

• file name

cd - Changing directories

We can change directories by using the cd command, followed by the directory we want to change to. Let's try changing to the root directory.

cd /

We can verify that we are in the root directory by using pwd. Zsh also shows us the working directory.

Root Directory

The files and directories on your computer are structured in a tree. The 'top' of the file system is know as the root directory (That may sound upside down, but in our case the root is at the top :)

Filesystem image

Home Directory

When logged in as a user, there will also be a home directory that represents your user's files. By default, the terminal will usually open in the home directory. As a shortcut, the tilde (~) can be used to change to the home directory. Just run cd ~.

cd ~

Absolute and Relative Paths

Absolute Path

An absolute path is the full path written out from the root. For example, the full path of a file may look like this:

/Users/romebell/Documents/profile.png

Navigating to this file would involve quite a lot of typing. Luckily, we can also use relative paths.

Relative Path

A relative path is a partial path relative to the current directory. For example, if Rome was already in /Users/romebell, a relative path for the file above would look like this:

Documents/profile.png

Note that /Users/romebell was left off, because Documents/profile.png is relative to /Users/romebell.

We can also use relative paths to go back one or more directories.

cd ..
cd ../..
cd .

Note that .. represents a link to the previous directory. The first command goes back one directory, and the second command goes back two directories. These are relative paths!

The third command doesn't take us anywhere. We can also use . to represent the current directory. Try it out to get used to these links.