allow excerpt length to be set on dashboard

[jidanni]

I note #7778, but why not also make the excerpt length something one can set from the dashboard without any plugins?
See also ​http://chrismeller.com/changing-the-length-of-the_excerpt-in-wordpress

[dwenaus]

I fully support this suggestion.

you should be able to pass two more optional variables to the excerpt function:

1. the length of the excerpt
2. the text to display at the end such as ... or continue

[ryan]

There is an excerpt_length filter. Not sure if this is worth a UI option.