  In the context of time domain astronomy, we present an offline detection
search of gamma-ray transients using a wild binary segmentation analysis called
FWBSB targeting both short and long gamma-ray bursts (GRBs) and covering the
soft and hard gamma-ray bands. We use NASA Fermi/GBM archival data as a
training and testing data set. This paper describes the analysis applied to the
12 NaI detectors of the Fermi/GBM instrument. This includes background removal,
change-point detection that brackets the peaks of gamma-ray flares, the
evaluation of significance for each individual GBM detector and the combination
of the results among the detectors. We also explain the calibration of the 10
parameters present in the method using one week of archival data. Finally, we
present our detection performance result for 60 days of a blind search analysis
with FWBSB by comparing to both the on-board and offline GBM search as well as
external events found by others surveys such as Swift-BAT. We detect 42/44
on-board GBM{events but also other gamma-ray flares at a rate of 1 per hour in
the 4-50 keV band. Our results show that FWBSB is capable of recovering
gamma-ray flares, including the detection of soft X-ray long transients. FWBSB
offers an independent identification of GRBs in combination with methods for
determining spectral and temporal properties of the transient as well as
localization. This is particularly useful for increasing the GRB rate and that
will help the joint detection with gravitational-wave events.
