Vim: delete until character for all lines containing a pattern
I'm learning the [power of g](http://vim.wikia.com/wiki/Power_of_g) and want to delete all lines containing an expression, to the end of the sentence (marked by a period). Like so:

` There was a little sheep. The sheep was black. There was another sheep.`

(command to find all sentences like `There was` and delete to the next period).

` The sheep was black.`

I've tried:

 1. `:g/There was/d\/\.` in an attempt to "delete forward until the next period" but I get a `trailing characters` error. 
 2. `:g/There was/df.` but get a `df. is not an editor command error.`

Any thoughts?
Vim: delete until character for all lines containing a pattern
===

I'm learning the [power of g](http://vim.wikia.com/wiki/Power_of_g) and want to delete all lines containing an expression, to the end of the sentence (marked by a period). Like so:

` There was a little sheep. The sheep was black. There was another sheep.`

(command to find all sentences like `There was` and delete to the next period).

` The sheep was black.`

I've tried:

 1. `:g/There was/d\/\.` in an attempt to "delete forward until the next period" but I get a `trailing characters` error. 
 2. `:g/There was/df.` but get a `df. is not an editor command error.`

Any thoughts?