shrinking logs: how much data will be reclaimed

Create Proc ShowSpace2BFreed
-- By JP de Jong 
-- Stored proc that enumerates all user databases and then checks the transaction log to
-- calculate the amount of space that can be freed when an DBCC SHRINKFILE (2) statement is issued
-- To shrink a logfile use the following syntax:
-- use databasename go dbcc shrinkfile (2)

as
set nocount on
declare @DBName varchar(100)

Create Table #TempLOG
(
fileid tinyint,
filesize int,
startoffset int not null,
fseqno int,
status tinyint,
parity int,
dateorLSN varchar (25)
)
alter table #TempLog add constraint PK_templog Primary Key (startoffset)

Create Table #TempFreeSizes
(
DBName varchar(100),
FreeSpaceMB bigint
)


select @DBname = min(name) from master..sysdatabases where name not in ('master','tempdb','model','msdb')

while @DBName <> '' 
begin
  insert into #TempLog exec ('use [' + @DBName + '] dbcc loginfo')

  insert into #TempFreeSizes
  select @DBName, isnull(sum(convert(bigint,filesize))/1024/1024,0) as FreeSpaceMB from #TempLog
  where startoffset > (select MAX(startoffset) from #TempLog 
  where status =2)

  truncate table #TempLog
  select @DBName = min(name) from master..sysdatabases where name not in ('master','tempdb','model','msdb') and name > @DBName

end 

insert #TempFreeSizes (DBName, FreeSpaceMB) select '<<Total>>', sum(freespaceMB) from #TempFreeSizes
Select * from #TempFreeSizes