.ldf File is 47GB but log space used only 1.4%, can i do this ?

Helllo guys

I'm running out of diskspace on my drive.

I saw that the .ldf file from my database (150GB) is now 47GB, but when i make the DBCC SQLPERF(logspace) statement, it sais that the log space used is only 1.4%

NOw i read that i can shrink my .ldf file with:

DBCC SHRINKFILE ('itstats_log', 30000) to 30GB. but i^'m a little bit scared, do i lose information in the .ldf file or will only be empty blocks cleaned ?

Or do i have to do it this way ?

DBCC SHRINKFILE ('itstats_log', 30000, TRUNCATEONLY)

Or is there a better way ? i really dont wanna lose important information in the transactionlog.

Thanks and Regards

Dominic