Absolute Paths

The paths we saw in the previous video were relative paths. 0:00 A relative path that works in one directory may not work if you change to 0:03 a different directory. 0:07 In this video, we're going to look at absolute paths which stay the same no 0:09 matter what directory you're in. 0:12 If I change up to the parent directory enough times, 0:15 eventually I'll reach a directory where I can't go any further. 0:17 So I'll say cd dot dot. 0:20 That will change me to my home directory. 0:22 CD dot, dot again. 0:25 That will change me to the slash home directory. 0:28 And CD dot dot one more time. 0:31 And this changes me to yet another directory. 0:37 If I try typing CD dot dot in this directory, it won't go anywhere. 0:40 If you imagine the file system like a tree with directories as branches, 0:45 the root directory would be the base that all the other branches spring out of. 0:49 The root directory doesn't have a name. 0:53 Its path is just a single slash. 0:56 Now, let me show you a simpler way to get to the root directory. 0:58 We started out in the home slash treehouse slash workspace directory. 1:03 Let me change back there. 1:07 CD, and I'll use tab completion here, home slash treehouse slash workspace. 1:08 Instead of typing CD dot dot, a bunch of times, 1:16 I can type CD slash to jump straight to the root directory. 1:19 This works no matter what directory I'm in. 1:23 Let's change to the home slash treehouse directory. 1:27 CD home slash treehouse. 1:29 Without the workspace directory on the end. 1:31 Once again, cd slash will take me back to the root directory. 1:36 An absolute path is one that starts at the root directory. 1:42 A slash by itself is the simplest absolute path. 1:47 It takes you straight to the root directory, 1:50 no matter where you are on the file system. 1:52 Let's find a different directory to go to. 1:55 I'll run ls to list the contents of this root directory. 1:58 And I'll change to this bin directory, cd bin slash. 2:01 Again, the slash is optional. 2:06 And now, I'll change back to the brief directory, cd slash. 2:09 Absolute paths start at the route directory. 2:11 But like other paths, you can then join other directory names onto them. 2:15 So suppose I was in the bin directory. 2:20 Cd bin. 2:22 And I want to change to the dev directory. 2:23 I couldn't do it with a relative path because it assumes I mean a dev directory 2:26 that exists within the bin directory. 2:30 But there is a dev directory within the root directory. 2:34 So if I start my path with the root directory, it will work. 2:37 Cd slash dev. 2:40 Suppose I now want to change to the etc directory within the root directory. 2:43 I don't have to change back to the root directory and then change to etc. 2:47 I can just cd slash etc to jump directly there. 2:51 Now, let's try a longer absolute path. 2:56 We started out in the home slash treehouse slash workspace directory. 2:58 Let's see if we can use an absolute path to get back there, 3:03 starting from the etc directory. 3:05 The home directory is within the root directory. 3:08 So we start with the root, slash, then type home slash treehouse. 3:10 And I'll start using tab completion now. 3:16 And workspace. 3:18 We're taken straight there. 3:21 I can also jump straight back to the etc directory, or any other directory, 3:24 by using it's absolute path, cd slash etc. 3:28 Absolute paths work with files, too. 3:32 Let's suppose I wanna print that starbunks menu again, but 3:35 I don't wanna leave the slash etc directory. 3:38 I can type the cat command name, and 3:40 then I can type the absolute path of the menu dot txt file. 3:43 It's a long path, so 3:46 I'm going to use tab completion to help me remember all the directory names. 3:47 I'm gonna start with slash h-o-m tab. 3:51 completes the home directory name. 3:55 T-r, that completes treehouse. 3:57 W-o completes workspace. 4:00 M-a-l completes mall. 4:04 S-t-tab completes starbunks. 4:06 And m-e-n-tab completes menu dot text. 4:09 There it is, the complete absolute path of the menu dot text files, 4:14 starting at the root directory. 4:17 And when I run the command, the program finds the file and prints its contents, 4:19 all without leaving the etc directory. 4:24 Absolute paths are bit less convenient than relative paths. 4:27 If you're currently in or near the same directory as a file, 4:31 you can use the file's absolute path to access it. 4:34 But it would probably be more convenient to use a relative path. 4:37 But when you're nowhere near the file or directory you want to access, 4:41 or if you don't even know where you are relative to your target, 4:44 you should use its absolute path. 4:48 Absolute paths eliminate all confusion about where a file or 4:50 a directory is within the file system. 4:53