I just tried that right now. I wrote *split in, then tested your command. This is what came out:

/write: unable to open 'C:\MARTIN\MIRC\logs\#fdsfds.irchighway.05\08\2005.log'

however, I tried it this way:

//write -ds,*split $+($logdir,$chan,.,$network,.,$date(yyyy),$date(mm),$date(dd),.log)

It seems to be "working", to some extent. However, it's not deleting the lines with *split in them. I experimented using -dstest , and it seems that it's not working somehow. :\