  We present an extensive analysis of the X2.0-class confined flare on 2014
October 27 in the great active region AR 12192, observed by the \emph{Interface
Region Imaging Spectrograph} and the \emph{Solar Dynamics Observatory}. The
slipping motion of the substructures within the negative-polarity flare ribbon
(R1) and continual reconnection-induced flows during the confined flare are
first presented. The substructures within ribbon R1 were observed to slip in
opposite directions at apparent speeds of 10-70 km s$^{-1}$. The slipping
motion exhibited the quasi-periodic pattern with a period of 80-110 s, which
can be observed since the flare start and throughout the impulsive phase of the
flare. Simultaneously quasi-periodic flows moved along a reverse-S shaped
filament, with an average period of about 90 s. The period of
reconnection-induced flows is similar to that of the slippage of ribbon
substructures, implying the occurrence of quasi-periodic slipping magnetic
reconnection. The spectral observations showed that the Si {\sc iv} line was
blueshifted by 50-240 km s$^{-1}$ at the location of the flows. During the
process of the flare, the filament did not show the rise phase and was not
associated with any failed eruption. The flare mainly consisted of two sets of
magnetic systems, with both of their east ends anchoring in ribbon R1. We
suggest that the slipping magnetic reconnection between two magnetic systems
triggers the confined flare.
