IPython As A Shell - Working With Directories

Due to the way IPython runs system commands by going out to a shell and then coming back the system cd won't work.

Fortunately IPython gives us the %cd magic command tht does work. It also keeps a history of directories visited and has an integrated bookmark system. It will also tab complete nicely, indeed just typing cd <tab> will give you a list of directories below your current location.

If you've downloaded this IPython notebook with the entire git repository then you can work along with me. I have a nice example directory tree for us to use.

Examples

In the examples below you can see they all start with /Users/tonyw/dev/MacSys - the first three parts are the directory where I keep all my github repositories and MacSys is the local name for this git repository. You should probably select Cell - All Output - Clear and remove all my output and ready for you to work through the examples

The directory history is kept in the list _dh

If there is no directory with the same name we don't need the -b

cd - takes us to the previous directory

cd -<n> will go to entry <n> in the history list.

cd --<text> will go to a directory that matches <text> in the history.

You will discover that bookmarks are saved from one IPython session to the next, but not the directory history.

I spent some time developing a way around this but discovered that a long directory history is less useful than a current one. I tend to have a longish bookmark list however.

Directory Stack

IPython also has a directory stack. We can push a directory onto the stack, pop the top one off or list the current stack.