Navigate through files and directories

First let us find out where we are by running a command called pwd:

!pwd

/Users/veit/cusy/trn/Python4DataScience/docs/workspace/ipython/unix-shell

Here, the response is the iPython chapter of the Jupyter tutorial in my home directory /Users/veit.

On Windows the home directory will look like C:\Documents and Settings\veit or C:\Users\veit and on Linux like /home/veit.

To see the contents of our directory, we can use ls:

!ls

create-delete.ipynb           index.rst
create-delete.ipynb.license   pipes-filters.ipynb
file-system.ipynb             pipes-filters.ipynb.license
file-system.ipynb.license     shell-variables.ipynb
grep-find.ipynb               shell-variables.ipynb.license
grep-find.ipynb.license

• a trailing / indicates a directory

• @ indicates a link

• * indicates an executable

Depending on your default options, the shell might also use colors to indicate whether an entry is a file or a directory.

ls options and arguments

!ls -F ../

debugging.ipynb
debugging.ipynb.license
display.ipynb
display.ipynb.license
examples.ipynb
examples.ipynb.license
extensions.rst
importing.ipynb
importing.ipynb.license
index.rst
magics.ipynb
magics.ipynb.license
mypackage/
myscript.py
shell.ipynb
shell.ipynb.license
start.rst
tab-completion-for-anything.png*
tab-completion-for-anything.png.license
tab-completion-for-modules.png*
tab-completion-for-modules.png.license
tab-completion-for-objects.png*
tab-completion-for-objects.png.license
unix-shell/

ls is the command, with the option -F and the argument ../.

• Options either start with a single dash (-) or two dashes (--), and they change the behavior of a command.

• Arguments tell the command what to operate on.

• Options and arguments are sometimes also referred as parameters.

• Each part is separated by spaces.

• Also, capitalisation is important, for example

  • ls -s will display the size of files and directories alongside the names,

  • while ls -S will sort the files and directories by size.

!ls -s

total 224
24 create-delete.ipynb            8 index.rst
 8 create-delete.ipynb.license   16 pipes-filters.ipynb
96 file-system.ipynb              8 pipes-filters.ipynb.license
 8 file-system.ipynb.license     16 shell-variables.ipynb
24 grep-find.ipynb                8 shell-variables.ipynb.license
 8 grep-find.ipynb.license

!ls -S

file-system.ipynb             create-delete.ipynb.license
grep-find.ipynb               file-system.ipynb.license
create-delete.ipynb           grep-find.ipynb.license
pipes-filters.ipynb           pipes-filters.ipynb.license
shell-variables.ipynb         shell-variables.ipynb.license
index.rst

Show all options and arguments

ls comes with a lot of other useful options. Using man you can print out the built-in manual page for the desired UNIX/Linux-command:

!man ls

LS(1)                       General Commands Manual                      LS(1)

NAME
     ls – list directory contents

SYNOPSIS
     ls [-@ABCFGHILOPRSTUWabcdefghiklmnopqrstuvwxy1%,] [--color=when]
        [-D format] [file ...]

DESCRIPTION
     For each operand that names a file of a type other than directory, ls
     displays its name as well as any requested, associated information.  For
     each operand that names a file of type directory, ls displays the names
     of files contained within that directory, as well as any requested,
     associated information.

     If no operands are given, the contents of the current directory are
     displayed.  If more than one operand is given, non-directory operands are
     displayed first; directory and non-directory operands are sorted
     separately and in lexicographical order.

     …

Illegal options

If you try to use an option that isn’t supported, the commands will usually print an error message, for example for:

!ls -z

ls: invalid option -- z
usage: ls [-@ABCFGHILOPRSTUWXabcdefghiklmnopqrstuvwxy1%,] [--color=when] [-D format] [file ...]

Hidden Files

With the -a option you can display all files:

!ls -a

.                             grep-find.ipynb
..                            grep-find.ipynb.license
.ipynb_checkpoints            index.rst
create-delete.ipynb           pipes-filters.ipynb
create-delete.ipynb.license   pipes-filters.ipynb.license
file-system.ipynb             shell-variables.ipynb
file-system.ipynb.license     shell-variables.ipynb.license

In addition to the hidden directories .. and ., you may also see a directory called .ipynb_checkpoints. This file usually contains snapshots of the Jupyter notebooks.

Show directory treeThe command tree lists contents of directories in a tree-like format.

!tree

.
├── create-delete.ipynb
├── create-delete.ipynb.license
├── file-system.ipynb
├── file-system.ipynb.license
├── grep-find.ipynb
├── grep-find.ipynb.license
├── index.rst
├── pipes-filters.ipynb
├── pipes-filters.ipynb.license
├── shell-variables.ipynb
└── shell-variables.ipynb.license

1 directory, 11 files

Change directory

At first it may seem irritating to some that they cannot use !cd to change to another directory.

!pwd

/Users/veit/cusy/trn/Python4DataScience/docs/workspace/ipython/unix-shell

!cd ..

!pwd

/Users/veit/cusy/trn/Python4DataScience/docs/workspace/ipython/unix-shell

The reason for this is that Jupyter uses a temporary subshell. If you want to change to another directory permanently, you have to use the magic command %cd. However, this also requires the Python package pickleshare.

%cd ..

/Users/veit/cusy/trn/Python4DataScience/docs/workspace/ipython

!pwd

/Users/veit/cusy/trn/Python4DataScience/docs/workspace/ipython

With the %automagic function, these can also be used without the preceding % character:

%automagic

Automagic is ON, % prefix IS NOT needed for line magics.

cd ..

/Users/veit/cusy/trn/Python4DataScience/docs/workspace

Absolute and relative Paths

cd .

/Users/veit/cusy/trn/Python4DataScience/docs/workspace

cd ../..

/Users/veit/cusy/trn/Python4DataScience

cd ..

/Users/veit/cusy/trn

cd /

/

cd

/Users/veit

cd ~

/Users/veit

cd /Users/veit

/Users/veit