This is guide on how to get any knife in CSGO using console commands. CSGO Knife Command.
Console commands:
sv_cheats 1
mp_drop_knife_enable 1 - to enable knife dropping
Console commands to get knives:

Karambit - give weapon_knife_karambit;ent_fire weapon_knife addoutput "classname weapon_knifegg"
Butterfly - give weapon_knife_butterfly;ent_fire weapon_knife addoutput "classname weapon_knifegg"
M9 Bayonet - give weapon_knife_m9_bayonet;ent_fire weapon_knife addoutput "classname weapon_knifegg"
Bayonet - give weapon_bayonet;ent_fire weapon_knife addoutput "classname weapon_knifegg"
Flip knife - give weapon_knife_flip;ent_fire weapon_knife addoutput "classname weapon_knifegg"
Shadow Daggers - give weapon_knife_push;ent_fire weapon_knife addoutput "classname weapon_knifegg"
Stiletto - give weapon_knife_stiletto;ent_fire weapon_knife addoutput "classname weapon_knifegg"
Skeleton - give weapon_knife_skeleton;ent_fire weapon_knife addoutput "classname weapon_knifegg"
Talon - give weapon_knife_widowmaker;ent_fire weapon_knife addoutput "classname weapon_knifegg"
Ursus - give weapon_knife_ursus;ent_fire weapon_knife addoutput "classname weapon_knifegg"
Paracord - give weapon_knife_cord;ent_fire weapon_knife addoutput "classname weapon_knifegg"
Nomad - give weapon_knife_outdoor;ent_fire weapon_knife addoutput "classname weapon_knifegg"
Survival - give weapon_knife_canis;ent_fire weapon_knife addoutput "classname weapon_knifegg"
Bowie - give weapon_knife_survival_bowie;ent_fire weapon_knife addoutput "classname weapon_knifegg"