KAGRA VIS Operations Manual - diaggui
diag is a command line tool developed at LIGO for doing spectrum measurements and transfer functions on the suspensions and other systems. See LIGO-T990013. It is hardly ever run manually, except when one of its components awg (the Arbitrary Waveform Generator) gets confused and needs to be reset. See ../TroubleShooting#tpclear. It is very useful in scripts however.
diaggui is a graphical user interface to diag.
Add more documentation on diaggui here.