Emacs bulk indent for Python

indent-region mapped to C-M-\ should do the trick.

In addition to indent-region, which is mapped to C-M-\ by default, the rectangle edit commands are very useful for Python. Mark a region as normal, then:

• C-x r t (string-rectangle): will prompt you for characters you'd like to insert into each line; great for inserting a certain number of spaces
• C-x r k (kill-rectangle): remove a rectangle region; great for removing indentation

You can also C-x r y (yank-rectangle), but that's only rarely useful.

Do indentation interactively.

1. Select the region to be indented.
2. C-x TAB.
3. Use arrows (<- and ->) to indent interactively.
4. Press Esc three times when you are done with the required indentation.

Copied from my post in: Indent several lines in Emacs

If you are programming Python using Emacs, then you should probably be using python-mode. With python-mode, after marking the block of code,

C-c > or C-c C-l shifts the region 4 spaces to the right

C-c < or C-c C-r shifts the region 4 spaces to the left

If you need to shift code by two levels of indention, or some arbitary amount you can prefix the command with an argument:

C-u 8 C-c > shifts the region 8 spaces to the right

C-u 8 C-c < shifts the region 8 spaces to the left

Another alternative is to use M-x indent-rigidly which is bound to C-x TAB:

C-u 8 C-x TAB shifts the region 8 spaces to the right

C-u -8 C-x TAB shifts the region 8 spaces to the left

Also useful are the rectangle commands that operate on rectangles of text instead of lines of text.

For example, after marking a rectangular region,

C-x r o inserts blank space to fill the rectangular region (effectively shifting code to the right)

C-x r k kills the rectangular region (effectively shifting code to the left)

C-x r t prompts for a string to replace the rectangle with. Entering C-u 8 <space> will then enter 8 spaces.

PS. With Ubuntu, to make python-mode the default mode for all .py files, simply install the python-mode package.