How to make a list of variables the header for a data frame [R]

Question

I have a data frame with no headers. It has 561 columns. It has the generic headers like so

V1 V2 ... V561

I also have a txt. file that has all of the variable names for that data frame. They are all in one column, like so:

1 tBodyAcc-mean()-X   
2 tBodyAcc-mean()-Y   
3 tBodyAcc-mean()-Z  
...  
561 angle(Z,gravityMean)

How would I go about reading that file in and putting all those variables as the column names for the original dataset?