Question

Vim is pretty powerful when editing by line – the search/replace tools are modeled to work linewise.

But what if I want to change a particular column across all lines? For example, how can I change the 80th column in my file to a # easily?

Answer 1

You can use a substitution where the pattern matches a specific column (\%c):

:%s/\%80c/#/<CR>

Or you can use block-wise visual mode:

gg80|CTRL+vGr#

The ‘virtualedit‘ option can be used to allow positioning the cursor to
positions where there is no actual character:

:set virtualedit