Using adaptive temporal pulse shaping of the driving 800 nm laser pulses, we demonstrate for the first time the complete control over the XUV spectrum of high-order harmonics, generated in a gas-filled hollow fiber. We achieve both the enhancement and the suppression of single or several selected harmonic orders. These arbitrarily shaped soft-x-ray spectra will allow for important modifications of the resulting harmonic pulses in the temporal domain. Experiments are in progress to determine the time structure of the shaped harmonics using a cross-correlation technique. This constitutes first steps
towards direct attosecond pulse shaping in the soft-x-ray domain. Moreover, we show that harmonic generation in a hollow-core fiber can be enhanced by coupling into a single fiber mode using a feedback-controlled adaptive two-dimensional spatial light modulator. Temporal and spatial tailoring of harmonics opens the way towards optimal control in the soft-x-ray domain.