Inserting a character in certain column

[Eugene Grosbein]

On Mon, Feb 25, 2008 at 09:52:21AM -0800, Szemer?dy G?bor wrote:

> I need to insert a character in certain column in all rows of the file 
> using vi.
> Please help

I don't use vi but remember it can use regexp like sed does:
the following examle inserts X after 5th column (read, in 6 column):

sed -E 's/^(.{5})(.*)/\1X\2/'

Eugene Grosbein