ent_fireconsole command is a debugging tool that fires inputs on entities. It's an essential tool for both programmers and mapmakers, allowing them to easily debug problems in a map's entity logic.
Different entities can handle different inputs. The easiest way to find out what inputs an entity handles is to use
ent_fire'sbuilt in autocomplete. Type
ent_fire <targetname>in the console, and the autocomplete system will give you a list of all the inputs known to the entity it found matching the <targetname>. If that doesn't work, the other easy way is to load up Hammer and place an entity of the same type, and look at the help for that entity. Entities will ignore inputs that they don't know how to handle." - Valve Develpoper Community
Let's talk about commands now.
For example, we going to use "generic_actor" entity.
But, you can use other entities.
ent_create generic_actor model models/gman.mdl
ent_setname jimmy (While looking at gman)
ent_fire jimmy setmodelscale 0.5 - little gman
ent_fire jimmy color -1 -red gman
WARNING! NEVER USE COMMAND LIKE "ent_fire !self becomeragdoll", THIS WILL CRASH YOUR GAME.