5.E: Creating Directories

5: Managing Files and Directories

5.C: Changing Directories - Carefully

By now you may be wondering if there is a quicker way to change directories. There is. With just one command you can do the equivalent of several list commands and change directory commands.

Because most of the files you access will be in or near your home directory, perhaps the most useful cd command is:

> cd ~
> cd

either one of which returns you to your home directory. Now check this by printing the working directory:
> pwd

The list command with recursive option ls -R no only lists names of files and directories, but also the contents of the directories:

> ls -FCR

The listing of your home directory should look something like:

Mwm             a.out*          eqns2.ms        public-html/    sample.doc
README.first    development/    plotoutfile.ps  s2

development:
data/   prog/

development/prog:
area.f 

To see what the recursive -R buys you, compare that listing to the output of ls -FC *:

Mwm             a.out*          plotoutfile.ps  sample.doc
README.first    eqns2.ms        s2

development:
data/   prog/

You can change directly to a specific directory without jumping from branch to branch on the directory tree. Just give cd the pathname of the target directory.

The pathname is the sequence of directories that lead to a file. It can be specified three ways. The full pathname has the form

> cd /u1/home/yourusername/development/prog

Here the leading / represents the topmost or root directory, and u1/home is where users' home directories are kept on some make-believe computer (it's not the same on all Unix systems). You can also give the pathname starting from the abbreviated form of your home directory, for example,

> cd ~/development/prog

Or, you can give the relative pathname from the present (working) directory in either of two forms

> cd development/prog

> cd ./development/prog

Notice that the subdirectories in pathnames are separted by the the / or "slash" symbol. (The / functions similarly to the backslash \ in DOS.) The exception to this being the leading slash as in

/u1/home/yourusername/development/prog

which represents the "root" or very top of the directory tree (owned by the user root). It is unlikely you will work in the root directory unless you become a system administrator. Nevertheless, it is educational for you to look at what's in the root directory, at least if you follow the cavaet, "look, but do not change":

> cd /
> ls -FC

If you want to know more about directory structure, try A Scientist's and Engineer's Guide to Workstations.

Remember, if you find yourself in the root directory, or anywhere else you do not want to be, or should not be, you can always return home. You do not even have to know where you are to get home, all roads lead you there:

cd
cd ~

Instead of going home, let's jump directly to our ~/development/prog directory:

> cd ~/development/prog

Now do a pwd to check where you are. You might want to try some exploring with the cd and ls commands before going on to Creating Directories.

5.E: Creating Directories

5: Managing Files and Directories

5.C: Changing Directories - Carefully

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