How to use pipe in IPython

Question

In a Linux terminal, when the output of one command is too long to read in one page, I can do this:

cat file | less

so that I can read and scroll up and down the output from the cat file.

How can I do this in IPython?

For example, I tried this and it didn't work:

whos | less

My original problem is that the output from whos is too much to be seen by doing Shift+Page Up and I don't want to change the scroll buffer.

Answer 1

Use of the pager should be automatic.

From the manual:

In order to configure less as your default pager, do the following:

1. Set the environment PAGER variable to less.
2. Set the environment LESS variable to -r (plus any other options you always want to pass to less by default). This tells less to properly interpret control sequences, which is how color information is given to your terminal.

For the bash shell, add to your ~/.bashrc file the lines:

export PAGER=less
export LESS=-r

Answer 2

In IPython, you can use %page obj to show the object obj using your standard pager (usually less). Alternatively, you can increase the scroll buffer of your terminal, which might be convenient in any case.

%page obj -- display object similar to IPython default display (repr-like), using pager if output size requires

%page -r obj -- display object similar to print, using pager if size requires

%page can only take a plain name or attribute reference. It cannot evaluate an arbitrary expression, but you can use a temporary variable to work around this limitationL

tmp = ex * pr + ess - ion
%page tmp

Answer 3

System shell access

Any input line beginning with a ! character is passed verbatim (minus the !, of course) to the underlying operating system. For example, typing !ls will run ‘ls’ in the current directory.

Source: http://ipython.scipy.org/doc/rel-0.9.1/html/interactive/reference.html#id1