Off topic:Trim the ID line of a fasta

Question

[SaltedPork]

I have a fasta file with some very silly ID's (straight from NCBI) that look like this:

>KF859747.1 HIV-1 isolate DEURF09UG005 from Uganda gag protein (gag) gene, complete cds; pol protein (pol) gene, partial cds; vif protein (vif), vpr protein (vpr), tat protein (tat), rev protein (rev), vpu protein (vpu), and envelope glycoprotein (env) genes, complete cds; and nonfunctional nef protein (nef) gene, complete sequence

If all I wanted was the >KF859747 part to be in my fasta, are there any nifty one liners to do this on the command line?