Navigating Directories with cd

Open a command window on any computer and the first thing you see is a prompt waiting for input. On its own, the prompt tells you very little. Yet every command you type afterward is interpreted against a location on the disk. Before you can use a command-line tool well, you need to know which location it is looking at.

This article answers one question: when you type a command and press return, which folder is the computer working in? The pattern of work is always the same. You type a command, the computer carries it out, any results appear in the window, and then a fresh prompt is shown for the next command. Because the window keeps going this way, the location you are working in carries forward from one command to the next. That carried-over location is the subject of the rest of this article.

Consider a command that refers to a file by a short name such as notes.txt. That name alone does not identify one file on the whole machine, because many folders may each hold a file with that name. The command line resolves short names by looking in one designated folder. That folder is the current directory, and whatever short names you type are understood as names inside it.

The current directory is therefore a kind of invisible context attached to your session. It does not appear as a separate file or setting that you open. It is simply the answer to the question every command implicitly asks: where should I look for the things you named? Because of this, the same short name can refer to different files depending on which folder you are standing in when you run the command.

Many command prompts make the current directory easy to spot, because the directory name is often displayed as part of the prompt itself. Reading the prompt is therefore the quickest way to check where you are before you run anything that depends on location. The exact text of a prompt varies between systems, so learn to recognize the folder name inside yours.

To see what the current directory holds, list its files. On Windows, the command is dir. On Linux and macOS, the command is ls. Both list the files in the current directory, and only that directory. Their output changes whenever the current directory changes.

The cd command changes the current directory. You follow cd with the name of the directory you want to move into, then press return. After that, short file names are interpreted inside the new directory, and the prompt usually reflects the new name.

The name you give to cd is itself interpreted relative to where you are standing right now. The starting location therefore matters a great deal. The same name can point to a different folder, or to no folder at all, depending on the current directory when you type it.

A new command window does not inherit the location of the window you closed. When a command window first opens, the current directory is set to your home directory. The home directory is the personal folder of the user, the place where that person's own files are stored.

This makes a fresh window a predictable place to begin. If you want files you saved personally, a newly opened window already points at the folder where they usually live. If you want to work somewhere else, you must move the current directory yourself with cd.