Is there a name for a rook moving in front of the pawn on a particular file? I have tried to make a diagram but cannot figure out how to do the FEN, sorry.

In a game that I played online somebody has done a rather strange thing, they moved their rook in front of the pawn on that file. In that particular game this actually resulted in them winning, but since I have never seen anything like this before I thought that it must be named something.
This manoeuvre is usually called a "rook lift".

The commentators Shahade and Seirawan try to popularise the term "rover" which is supposed to be short for "rook up and over". It's a bit of a running gag on their shows.

Here's an example in which the rook lift was pretty surprising for the live commentators:

[Event "Kramnik vs Deep Fritz"]
[Site "Bonn GER"]
[Date "2006.12.05"]
[EventDate "?"]
[Round "6"]
[Result "1-0"]
[White "Deep Fritz (Computer)"]
[Black "Vladimir Kramnik"]
[ECO "B90"]
[WhiteElo "?"]
[BlackElo "?"]
[PlyCount "93"]
[fen "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"]

1.e4 c5 2.Nf3 d6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 a6 6.Bc4 e6 7.O-O
Be7 8.Bb3 Qc7 9.Re1 Nc6 10.Re3 O-O 11.Rg3 Kh8 12.Nxc6 bxc6
13.Qe2 a5 14.Bg5 Ba6 15.Qf3 Rab8 16.Re1 c5 17.Bf4 Qb7 18.Bc1
Ng8 19.Nb1 Bf6 20.c3 g6 21.Na3 Qc6 22.Rh3 Bg7 23.Qg3 a4 24.Bc2
Rb6 25.e5 dxe5 26.Rxe5 Nf6 27.Qh4 Qb7 28.Re1 h5 29.Rf3 Nh7
30.Qxa4 Qc6 31.Qxc6 Rxc6 32.Ba4 Rb6 33.b3 Kg8 34.c4 Rd8 35.Nb5
Bb7 36.Rfe3 Bh6 37.Re5 Bxc1 38.Rxc1 Rc6 39.Nc3 Rc7 40.Bb5 Nf8
41.Na4 Rdc8 42.Rd1 Kg7 43.Rd6 f6 44.Re2 e5 45.Red2 g5 46.Nb6
Rb8 47.a4 1-0