A simple unstuck script in gmod

unstuck.lua

-- TODO: Nocollided props still trigger even with MASK_PLAYERSOLID!
---------------------------------------------------------------
local ply = nil

-- WeHateGarbage
local t = {start=nil,endpos=nil,mask=MASK_PLAYERSOLID,filter=nil}
local function PlayerNotStuck()

	t.start = ply:GetPos()
	t.endpos = t.start
	t.filter = ply
	
	return util.TraceEntity(t,ply).StartSolid == false
	
end

local NewPos = nil
local function FindPassableSpace( direction, step )

	local i = 0
	while ( i < 100 ) do
		local origin = ply:GetPos()

		--origin = VectorMA( origin, step, direction )
		origin = origin + step * direction
		
		ply:SetPos( origin )
		if PlayerNotStuck( ply ) then
			NewPos = ply:GetPos()
			return true
		end
		i = i + 1
	end
	return false
end

-- 	
--	Purpose: Unstucks player
--	Note: Very expensive to call, you have been warned!
--
local function UnstuckPlayer( pl )
	ply = pl

	NewPos = ply:GetPos()
	local OldPos = NewPos
	
	if not PlayerNotStuck( ply ) then
	
		local angle = ply:GetAngles()
		
		local forward = angle:Forward()
		local right = angle:Right()
		local up = angle:Up()
		
		local SearchScale = 1 -- Increase and it will unstuck you from even harder places but with lost accuracy. Please, don't try higher values than 12

		if	not FindPassableSpace( forward, SearchScale ) and	-- forward
			not FindPassableSpace( right, SearchScale ) and  	-- right
			not FindPassableSpace( right, -SearchScale ) and 	-- left
			not FindPassableSpace( up, SearchScale ) and    	-- up
			not FindPassableSpace( up, -SearchScale ) and   	-- down
			not FindPassableSpace( forward, -SearchScale )   	-- back
		then								
			--Msg( "Can't find the world for player "..tostring(ply).."\n" )
			return false
		end
		
		if OldPos == NewPos then 
			return true -- Not stuck?
		else
			ply:SetPos( NewPos )
			if SERVER and ply and ply:IsValid() and ply:GetPhysicsObject():IsValid() then
				if ply:IsPlayer() then
					ply:SetVelocity(vector_origin)
				end
				ply:GetPhysicsObject():SetVelocity(vector_origin) -- prevents bugs :s
			end
		
			return true
		end
		
	end
	
	
end

---------------------------------------------------------------

local meta = FindMetaTable( "Player" )
if not meta then return end

--	Unstucks a player
-- returns:
--	true:	Unstucked
--	false:	Could not UnStuck
--	else:	Not stuck 
--
function meta:UnStuck()
	return UnstuckPlayer(self)
end

---------------------------------------------------------------
-- CONFIG -----------------------------------------------------
---------------------------------------------------------------

local config = {} -- ignore

-- Available chat commands for us_unstuck console command
config.ChatCommands = {
		
		"!unstuck",
		"!stuck",
		"/unstuck",
		"/stuck"
		
}

-- Players of these teams are not allowed to use the unstuck command
config.ExcludedTeams = {
	
		"TEAM_PROPS"

}

-- Number of seconds a player has to wait until (s)he can use the unstuck command again
config.Wait = 10

---------------------------------------------------------------

concommand.Add( "us_unstuck", function( pl )

	if not IsValid( pl ) then return end
	
	if not pl:Alive() then
		pl:ChatPrint( "You ain't alive." )
		return
	end

	for _,team in pairs( config.ExcludedTeams ) do
		if _G[team] ~= nil and _G[team] == pl:Team() then
			pl:ChatPrint( "Sorry! You aren't allowed to do this in your team!" )
			return
		end
	end

	local CurrentTime = CurTime()
	
	if pl.lastUnStuckTime then
		if pl.lastUnStuckTime + config.Wait > CurrentTime then
			local waittime, s = config.Wait - math.floor( CurrentTime - pl.lastUnStuckTime ), ""
			if waittime ~= 1 then s = "s" end
			pl:ChatPrint( "You might want to wait another " .. tostring( waittime ) .. " second" .. s .. "." )
			return
		end
	end
	
	local unstuck = pl:UnStuck()
	if unstuck == true then
		pl:ChatPrint( "Unstuck successful!" )
	elseif unstuck == false then
		pl:ChatPrint( "Unstuck not possible (No free space found)." )
	else
		pl:ChatPrint( "You are not stuck." )
	end
	
	pl.lastUnStuckTime = CurTime()
	
end )

hook.Add( "PlayerSay", "Unstuck Command", function( pl, text )
	
	if table.HasValue( config.ChatCommands, string.lower(text) ) then
		pl:ConCommand( "us_unstuck" )
		--return false
	end
	
end )

Sorry for the late answer, according to my experiences this script still works even though there are better solutions.
You may not experience this problem anymore if you change SearchScale to 2 or 3.

Where do i put this script?

I put it in ...\Steam\steamapps\common\GarrysMod\garrysmod\lua\autorun

I agree with tetra-fox, this command doesn't work on my prop hunt server. It just says the same thing, Unstuck not possible (No free space found).