There is an error on <v.edit> manual page in all versions (6.4 / 6.5 / 7.0).
Given:
…
Select from given bounding box all lines longer then 200 map units:
v.edit map=roads tool=select bbox=598260,4919730,605100,4926240 query=length thresh=-1,0,1000
…
Should be:
…
Select from given bounding box all lines longer then 200 map units:
v.edit map=roads tool=select bbox=598260,4919730,605100,4926240 query=length thresh=-1,0,200
…
Please, make s/1000/200/ 