Regular Expression to recognise truncated forms of search string?

I'm trying to formulate a regular expression which will recognise the search term truncated by any nu开发者_JAVA技巧mber of characters from the right.

For example, if the search term is "pickle", the regex should recognise "pi", "pick" but not "pickaxe".

Initially I came up with the following:

p(i(c(k(l(e)?)?)?)?)?

That works perfectly, but seems a crude way of doing it. Is there a better way of doing this? I had a look around for something similar to what I want, but I'm not entirely sure what to search for.

Due to the way regex works, yes, that's basically the most concise form.