This documentation covers IPython versions 6.0 and higher. Beginning with version 6.0, IPython stopped supporting compatibility with Python versions lower than 3.3 including all versions of Python 2.7.
If you are looking for an IPython version compatible with Python 2.7, please use the IPython 5.x LTS release and refer to its documentation (LTS is the long term support release).
IPython as a system shell¶
It is possible to adapt IPython for system shell usage. In the past, IPython shipped a special ‘sh’ profile for this purpose, but it had been quarantined since 0.11 release, and in 1.0 it was removed altogether. Nevertheless, much of this section relies on machinery which does not require a custom profile.
You can set up your own ‘sh’ profile to be different from the default profile such that:
- Prompt shows the current directory (see Prompt customization)
- Make system commands directly available (in alias table) by running the
%rehashxmagic. If you install new programs along your PATH, you might want to run
%rehashxto update the alias table
%autocallto full mode
Rather than manipulating os.environ directly, you may like to use the magic
%env command. With no arguments, this displays all environment variables
and values. To get the value of a specific variable, use
%env var. To set
the value of a specific variable, use
%env foo bar,
%env foo=bar. By
default values are considered to be strings so quoting them is unnecessary.
However, Python variables are expanded as usual in the magic command, so
%env foo=$bar means “set the environment variable foo to the value of the
Once you run
%rehashx, all of your $PATH has been loaded as IPython aliases,
so you should be able to type any normal system command and have it executed.
%unalias? for details on the alias facilities. See also
%rehashx? for details on the mechanism used to load $PATH.
Since each command passed by IPython to the underlying system is executed in a subshell which exits immediately, you can NOT use !cd to navigate the filesystem.
IPython provides its own builtin
%cd magic command to move in the
filesystem (the % is not required with automagic on). It also maintains
a list of visited directories (use
%dhist to see it) and allows direct
switching to any of them. Type
cd? for more details.
%dirs are provided for directory stack handling.
String lists (IPython.utils.text.SList) are handy way to process output
from system commands. They are produced by
var = !cmd syntax.
First, we acquire the output of ‘ls -l’:
[Q:doc/examples]|2> lines = !ls -l == ['total 23', '-rw-rw-rw- 1 ville None 1163 Sep 30 2006 example-demo.py', '-rw-rw-rw- 1 ville None 1927 Sep 30 2006 example-embed-short.py', '-rwxrwxrwx 1 ville None 4606 Sep 1 17:15 example-embed.py', '-rwxrwxrwx 1 ville None 1017 Sep 30 2006 example-gnuplot.py', '-rwxrwxrwx 1 ville None 339 Jun 11 18:01 extension.py', '-rwxrwxrwx 1 ville None 113 Dec 20 2006 seteditor.py', '-rwxrwxrwx 1 ville None 245 Dec 12 2006 seteditor.pyc']
Now, let’s take a look at the contents of ‘lines’ (the first number is the list element number):
[Q:doc/examples]|3> lines <3> SList (.p, .n, .l, .s, .grep(), .fields() available). Value: 0: total 23 1: -rw-rw-rw- 1 ville None 1163 Sep 30 2006 example-demo.py 2: -rw-rw-rw- 1 ville None 1927 Sep 30 2006 example-embed-short.py 3: -rwxrwxrwx 1 ville None 4606 Sep 1 17:15 example-embed.py 4: -rwxrwxrwx 1 ville None 1017 Sep 30 2006 example-gnuplot.py 5: -rwxrwxrwx 1 ville None 339 Jun 11 18:01 extension.py 6: -rwxrwxrwx 1 ville None 113 Dec 20 2006 seteditor.py 7: -rwxrwxrwx 1 ville None 245 Dec 12 2006 seteditor.pyc
Now, let’s filter out the ‘embed’ lines:
[Q:doc/examples]|4> l2 = lines.grep('embed',prune=1) [Q:doc/examples]|5> l2 <5> SList (.p, .n, .l, .s, .grep(), .fields() available). Value: 0: total 23 1: -rw-rw-rw- 1 ville None 1163 Sep 30 2006 example-demo.py 2: -rwxrwxrwx 1 ville None 1017 Sep 30 2006 example-gnuplot.py 3: -rwxrwxrwx 1 ville None 339 Jun 11 18:01 extension.py 4: -rwxrwxrwx 1 ville None 113 Dec 20 2006 seteditor.py 5: -rwxrwxrwx 1 ville None 245 Dec 12 2006 seteditor.pyc
Now, we want strings having just file names and permissions:
[Q:doc/examples]|6> l2.fields(8,0) <6> SList (.p, .n, .l, .s, .grep(), .fields() available). Value: 0: total 1: example-demo.py -rw-rw-rw- 2: example-gnuplot.py -rwxrwxrwx 3: extension.py -rwxrwxrwx 4: seteditor.py -rwxrwxrwx 5: seteditor.pyc -rwxrwxrwx
Note how the line with ‘total’ does not raise IndexError.
If you want to split these (yielding lists), call fields() without arguments:
[Q:doc/examples]|7> _.fields() <7> [['total'], ['example-demo.py', '-rw-rw-rw-'], ['example-gnuplot.py', '-rwxrwxrwx'], ['extension.py', '-rwxrwxrwx'], ['seteditor.py', '-rwxrwxrwx'], ['seteditor.pyc', '-rwxrwxrwx']]
If you want to pass these separated with spaces to a command (typical for lists if files), use the .s property:
[Q:doc/examples]|13> files = l2.fields(8).s [Q:doc/examples]|14> files <14> 'example-demo.py example-gnuplot.py extension.py seteditor.py seteditor.pyc' [Q:doc/examples]|15> ls $files example-demo.py example-gnuplot.py extension.py seteditor.py seteditor.pyc
SLists are inherited from normal Python lists, so every list method is available:
Real world example: remove all files outside version control¶
First, capture output of “hg status”:
[Q:/ipython]|28> out = !hg status == ['M IPython\\extensions\\ipy_kitcfg.py', 'M IPython\\extensions\\ipy_rehashdir.py', ... '? build\\lib\\IPython\\Debugger.py', '? build\\lib\\IPython\\extensions\\InterpreterExec.py', '? build\\lib\\IPython\\extensions\\InterpreterPasteInput.py', ...
(lines starting with ? are not under version control).
[Q:/ipython]|35> junk = out.grep(r'^\?').fields(1) [Q:/ipython]|36> junk <36> SList (.p, .n, .l, .s, .grep(), .fields() availab ... 10: build\bdist.win32\winexe\temp\_ctypes.py 11: build\bdist.win32\winexe\temp\_hashlib.py 12: build\bdist.win32\winexe\temp\_socket.py
Now we can just remove these files by doing ‘rm $junk.s’.
The .s, .n, .p properties¶
.s property returns one string where lines are separated by
single space (for convenient passing to system commands). The
property return one string where the lines are separated by a newline
(i.e. the original output of the function). If the items in string
list are file names,
.p can be used to get a list of “path” objects
for convenient file manipulation.