How to fast drop pistol or first weapon?

When we are watching pro players, they can drop pistol or even first weapon really fast and even when they are running with knife...

What is the bind to drop pistol, drop first weapon and keep the current weapon (or last maybe) ?

Thank you

There's no built-in method for doing this.

If you use console commands, you can set drop binds for individual guns and combine them to make binds for gun types.

This thread on HLTV has a good set of console binds for different weapon types (note this post is from 2012 and I haven't tested personally; but it all seems like reasonable console commands).

As per the thread I found these, the credit for these scripts goes to Q-bA11 @ scripting.elxdraco.net.

Drop C4 (and leave a message):

alias fdbomb "drop weapon_c4; w; say_team Bomb dropped!" 
//; bind "yourkey" "fdbomb"

Drop primary weapon:

alias fdprimary "drop weapon_famas;drop weapon_galil;drop weapon_m4a1;drop weapon_ak47;drop weapon_aug;fdprimary.1" 
alias fdprimary.1 "drop weapon_sg552;drop weapon_scout;drop weapon_awp;drop weapon_sg550;fdprimary.2" 
alias fdprimary.2 "drop weapon_g3sg1;drop weapon_m3;drop weapon_xm1014;drop weapon_mac10;fdprimary.3" 
alias fdprimary.3 "drop weapon_mp;drop weapon_mp5navy;drop weapon_ump45;drop weapon_p90;drop weapon_m249" 
//; bind "yourkey" "fdprimary"

Drop Pistols:

alias fdpistol "drop weapon_glock18; drop weapon_usp; drop weapon_p228; drop weapon_deagle; drop weapon_elite; drop weapon_fiveseven" 
//; bind "yourkey" "fdpistol"

Drop all:

//;alias fdall "fdbomb;fdprimary;fdpistol" 
//; bind "yourkey" "fdall"

Obviously you need to change the "yourkey" in the ;bind "yourkey" lines for each to get them on whatever key you choose.

Let me know if that doesn't work as-is. I think the "/"'s might not be needed.

The basic command to drop whatever you are holding is drop. To switch to another weapon slot the commands slot1, slot2, slot3 (...) are used. Usually you should be fine if you have both the slots and the drop command on a seperate bind. There is not really a scenario where dropping a gun as fast as possible is required.

If you really want to drop something as fast as possible you can combine the commands. To drop your main weapon you can use:

bind "x" "slot1; drop;"