better handling of unset $FSLDIR

Author: TheChymera

nipype/interfaces/fsl/model.py

@@ -197,8 +197,14 @@ def _create_ev_files(
                     ev_parameters['cond_file'] = evfname
                     ev_parameters['ev_num'] = num_evs[0]
                     ev_parameters['ev_name'] = name
-                    ev_parameters['fsldir'] = os.environ['FSLDIR']
                     ev_parameters['tempfilt_yn'] = do_tempfilter
+                    try:
+                        ev_parameters['fsldir'] = os.environ['FSLDIR']
+                    except KeyError:
+                        if basis_key == 'flobs':
+                            raise Exception('FSL environment variables not set')
+                        else:
+                            ev_parameters['fsldir'] = '/usr/share/fsl'
                     try:
                         ev_parameters['temporalderiv'] = int(bool(ev_parameters.pop('derivs')))
                     except KeyError:

nipype/interfaces/script_templates/feat_ev_custom.tcl

@@ -34,5 +34,5 @@ set fmri(deriv_yn$ev_num) $temporalderiv
 set fmri(custom$ev_num) "$cond_file"
 
 # Optimal/custom HRF convolution file
-set fmri(default_bfcustom) "${fsldir}etc/default_flobs.flobs/hrfbasisfns.txt"
+set fmri(default_bfcustom) "${fsldir}/etc/default_flobs.flobs/hrfbasisfns.txt"
 set fmri(bfcustom) "$bfcustompath"