Debian GNU/Linux.  The other platforms and binaries should not differ but you where told just in case :).

begin firing
In the case of Nexuiz is activates the current weapons primary fire mode

move backward

activate button10 (behavior depends on mod)

activate button11 (behavior depends on mod)

activate button12 (behavior depends on mod)

activate button13 (behavior depends on mod)

activate button14 (behavior depends on mod)

activate button15 (behavior depends on mod)

activate button16 (behavior depends on mod)

activate button3 (behavior depends on mod)
In the case of Nexuiz this activates the current weapons secondary fire mode (there is also the alias +attack2 which is used in Nexuiz to make it clear what it does)

activate button4 (behavior depends on mod)
In the case of Nexuiz this zooms your view (there is also the alias +zoom which is used in Nexuiz to make it clear what it does)

activate button5 (behavior depends on mod)
In the case of Nexuiz this makes the player crouch (there is also the alias +crouch which is used in Nexuiz to make it clear what it does)

activate button6 (behavior depends on mod)
In the case of Nexuiz this activates the grappling hook (there is also the alias +hook which is used in Nexuiz to make it clear what it does)

activate button7 (behavior depends on mod)
In the case of Nexuiz this shows the current game info (there is also the alias +show_info which is used in Nexuiz to make it clear what it does)

activate button8 (behavior depends on mod)

activate button9 (behavior depends on mod)

move forward

jump
Can also be used to swim upwards while submerged. Note that unlike with other +commands, the player will have to release the jump key and press it again to be allowed to jump again. This is a deliberate restriction by design and does not hold true for moving upwards in water

activate keyboard looking mode, do not recenter view
When active, causes +forward and +back to turn the view up/down instead of moving in that direction (pretty useless. Learn to use the mouse to look. But "keyboard-only" matches can be very funny)

turn left

look downward

look upward

activate mouse looking mode, do not recenter view
This is on by default (see the variable freelook).

swim downward

strafe left

strafe right

swim upward

turn right

show scoreboard

activate run mode (faster movement and turning)
Actually the movement speeds are modified by the variable cl_movespeedkey which is normaly set to 2. So this makes the player twice as fast. If you set it to 0.5 it slows down to half the normal speed.

activate strafing mode (move instead of turn)
Causes +left and +right to strafe left/right instead of turning that way

use something (may be used by some mods)

stop firing

stop moving backward

deactivate button10

deactivate button11

deactivate button12

deactivate button13

deactivate button14

deactivate button15

deactivate button16

deactivate button3

deactivate button4

deactivate button5

deactivate button6

deactivate button7

deactivate button8

deactivate button9

stop moving forward

end jump (so you can jump again)

deactivate keyboard looking mode

stop turning left

stop looking downward

stop looking upward

deactivate mouse looking mode

stop swimming downward

stop strafing left

stop strafing right

stop swimming upward

stop turning right

hide scoreboard

deactivate run mode

deactivate strafing mode

stop using something

create a script function (parameters are passed in as $1 through $9, and $* for all parameters)
Allows you to create an alias for an other command or a whole set of commands. For example, alias switch_laser "impulse 1" will create a new command that is the same as typing "impulse 1" to switch to the laser (but is easier to remember).
You can also create your own +/- commands:
alias +laser "impulse 1; wait; +attack"
alias -laser "-attack; wait; impulse 2"
This command should switch to the laser, start shooting, and when you release the button stop shooting and switch to the shotgun.
alias "+scores" "+showscores; ping"
alias "-scores" "-showscores"
This command shows the scoreboard and also the ping times of all players.
You can't save aliases in your config.cfg as it gets rewritten everytime Nexuiz is closed. So you have to store new aliases in a "autoexec.cfg" file in your Nexuiz/data directory (or ~/.nexuiz/data on linux/mac).

signon 3 (client asks server to start sending entities, and will go to signon 4 (playing) when the first entity update is received)

send an impulse number to server to select the first usable weapon out of several (example: bind ALT "bestweapon 8 7 6 5 4 3 2 1")

briefly flashes a bright color tint on view (used when items are picked up)

binds a command to the specified key in bindmap 0
Can also bind an alias to a key. For example:
bind mouse1 "+attack"
mouse1 is the attack key
bind r "impulse 1"
r switches to the laser
Some keys that can not be typed need to be indentified by the name (tab, enter, escape, space, backspace, uparrow, downarrow, leftarrow, rightarrow, alt, ctrl, shift, f1, f2, f3, f4, f5, f6, f7, f8, f9, f10, f11, f12, ins, del, pgdn, pgup, home, end, pause, mwheelup, mwheeldown, mouse1, mouse2, mouse3, mouse4, mouse5, mouse6, mouse7, mouse8, mouse9, mouse10, mouse11, mouse12, mouse13, mouse14, mouse15, mouse16, numlock, capslock, scrollock, kp_home, kp_uparrow, kp_pgup, kp_leftarrow, kp_rightarrow, kp_end, kp_downarrow, kp_pgdn, kp_ins, kp_del, kp_slash, kp_0, kp_1, kp_2, kp_3, kp_4, kp_5, kp_6, kp_7, kp_8, kp_9, kp_period, kp_divide, kp_multiply, kp_minus, kp_plus, kp_enter, kp_equals, joy1, joy2, joy3, joy4, joy5, joy6, joy7, joy8, joy9, joy10, joy11, joy12, joy13, joy14, joy15, joy16, aux1, aux2, aux3, aux4, aux5, aux6, aux7, aux8, aux9, aux10, aux11, aux12, aux13, aux14, aux15, aux16, aux17, aux18, aux19, aux20, aux21, aux22, aux23, aux24, aux25, aux26, aux27, aux28, aux29, aux30, aux31, aux32, semicolon, tilde, backquote, quote, apostrophe).

QW command to set bottom color without changing top color

execute a CD drive command (cd on/off/reset/remap/close/play/loop/stop/pause/resume/eject/info)
cd play 5
[Plays track 5 of cd or fakecd directories]
The argument (in the previous example "5") should be between 1 and 255 (inclusively), otherwise it will be wrapped to stay between 0 (!) and 255 (inclusively). Track 0 is invalid.
cd play track666
[Plays track666.ogm or track666.wav from fakecd directories]
"loop" can be used instead of "play", to repeatedly play a track.
cd loop track006
[Plays track006.ogm or track006.wav from fakecd directories]

select an SDL-detected CD drive by number

gradually recenter view (stop looking up/down)

change to another level, bringing along all connected clients

sent by qw servers to tell client to wait for level change

reloads effectinfo.txt

clear console history

send a console commandline to the server (used by some mods)

lists all console commands beginning with the specified prefix

change your player shirt and pants colors

output console history to a file (see also log_file)

connect to a server by IP address or hostname
Connects to the given server. Use "connect IP_OR_HOSTNAME" or "connect IP_OR_HOSTNAME:PORT". The default port is 26000 if not specified.

download data from an URL and add to search path

stores the current values of all cvars into their default values, only used once during startup after parsing default.cfg

sets all cvars to their locked default values

sets all non-saved cvars to their locked default values (variables that will not be saved to config.cfg)

sets all saved cvars to their locked default values (variables that will be saved to config.cfg)

lists all console variables beginning with the specified prefix

restart looping demos defined by the last startdemos command

list files in searchpath matching an * filename pattern, one per line

disconnect from server (or disconnect all clients if running a server)

print a message to the console (useful in scripts)
alias crouch_on "+crouch; echo now crouching; alias crouch_toggle crouch_off"
alias crouch_off "-crouch; echo now standing; alias crouch_toggle crouch_on"
alias crouch_toggle "crouch_on"
bind x crouch_toggle.
pressing x will make the player crouch, pressing it again will make the player stand

print information on network entities known to client

render a cubemap (skybox) of the current scene

execute a script file

fly mode (flight)
Free movement in all xyz axis. sv_cheats needs to be set to 1 for this to work. This is usefull for testing / debuging maps and for screenshots. Entering fly again will disable fly mode.

set global fog parameters (density red green blue)
This command needs 4 arguments. The first one is the distance to the point when the fog is "solid", the next three is normalized rgb (red green blue) values (ie they range from 0 to 1, not 0 to 255) Example: "fog 0.5 0.4 0 0" this creates a rather thick darkish red fog.

recenters view (stops looking up/down)

rescans filesystem for new pack archives and any other changes

allows client to modify their userinfo

internal use only, sent by server to client to update client's local copy of serverinfo string

changes active gamedir list (can take multiple arguments), not including base directory (example usage: gamedir ctf)

alter inventory
Give an item to the player. I.E. give 3 will give you the machinegun. This needs sv_cheats to be set to 1.

set texture filtering mode (GL_NEAREST, GL_LINEAR, GL_LINEAR_MIPMAP_LINEAR, etc)
Returns/sets the OpenGL texture mode. The non-mipmapping modes have typical 'flickering', as large textures have to be reduced to a couple of pixels for faraway objects, whereas with mipmapping enabled there will already be a texture almost the right size, thus keeping consistency. The default mode is by far the best-looking.

god mode (invulnerability)
This needs sv_cheats to be set to 1

send a heartbeat to the master server (updates your server information)

send an impulse number to server (select weapon, use item, etc)
Example: impulse 1
The following numbers (and more) currently (2008-01-04) exist:
1 Laser
2 Shotgun
3 Machine Gun
4 Grenade Launcher
5 Electro
6 Crylink
7 Nex Gun
8 Hagar
9 Rocket Launcher
11 Last weapon (also available as alias "weaplast")

binds a command to the specified key in the selected bindmap

selects active foreground and background (used only if a key is not bound in the foreground) bindmaps for typing

removes command on the specified key in the selected bindmap

kick a player off the server by number or name
Use the command status to find out the players #number. kick # NUMBER REASON will then kick him off the server. The reason is not needed but its good when given.

die instantly
Not very useful in normal game play. Can be used when falling down a spacemap to be able to respawn faster because you do not have to wait till you fall to death.

load a saved game file

reset everything and reload configs

load a skybox by basename (for example loadsky mtnsun_ loads mtnsun_ft.tga and so on)

list files in searchpath matching an * filename pattern, multiple per line

kick everyone off the server and start a new level

list information about available maps

sets limit on how many players (or bots) may be connected to the server at once
Can not be changed while the server is running.

prints memory pool information (or if used as memlist 5 lists individual allocations of 5K or larger, 0 lists all allocations)

prints memory system statistics

restart menu system (reloads menu.dat

input a chat message to say to everyone

input a chat message to say to only your team

prints a list of loaded models

load a model

change your player name
Enter name alone and it will print your current name. Enter name YourNewName to change you players name to YourNewName. You can use ^NUMBER to add color to your name. ^0MyCool^3Name will change your name to MyCoolName with the first part black the second part yellow. The numbers are:
^0 black
^1 red
^2 green
^3 yellow
^4 blue
^5 cyan
^6 magenta
^7 white

tests if a given IP is banned

query dp master servers and print all server information

query qw master servers and print all server information

print network statistics

sends next fragment of current upload buffer (screenshot for example)

noclip mode (flight without collisions, move through walls)

notarget mode (monsters do not see you)

send a packet to the specified address:port containing a text string

print searchpath (game directories and archives)

pause the game (if the server allows pausing)

pause demo playback (can also safely pause demo recording if using QUAKE, QUAKEDP or NEHAHRAMOVIE protocol, useful for making movies)

print ping times of all players on the server
Ping it the time between "request and response" to/from the server. Lower values are better.

command sent by server containing client ping and packet loss values for scoreboard, triggered by pings command from client (not used by QW servers)

command sent by clients to request updated ping and packetloss of players on scoreboard (originally from QW, but also used on NQ servers)

play a sound at your current location (not heard by anyone else)

play a sound globally throughout the level (not heard by anyone else)

watch a demo file

change your player model

change your player skin number

play a .dpv video file

play a sound at the specified volume level at your current location (not heard by anyone else)

display point file produced by qbsp when a leak was detected in the map (a line leading through the leak hole, to an entity inside the level)

signon 1 (client acknowledges that server information has been received)

print all data about an entity number in the selected VM (server, client, menu)

prints number of active entities in the selected VM (server, client, menu)

set a property on an entity number in the selected VM (server, client, menu)

changes value of a specified property of a specified entity in the selected VM (server, client, menu)

prints usage statistics on properties (how many entities have non-zero values) in the selected VM (server, client, menu)

prints value of a specified global variable in the selected VM (server, client, menu)

prints all global variables in the selected VM (server, client, menu)

sets value of a specified global variable in the selected VM (server, client, menu)

prints a disassembly (QuakeC instructions) of the specified function in the selected VM (server, client, menu)

prints execution statistics about the most used QuakeC functions in the selected VM (server, client, menu)

quit the game

removes all world lights (let there be darkness!)

store a copy of all properties (except origin) of the selected light

changes a property on the selected light

changes a property on ALL lights at once (tip: use radiusscale and colorscale to alter these properties)

prints documentation on console commands and variables in rtlight editing system

load lights from .ent file or map entities (ignoring .rtlights or .lights file)

load lights from .lights file (ignoring .rtlights or .ent files and map entities)

apply the stored properties onto the selected light (making it exactly identical except for origin)

reloads rtlights file (or imports from .lights file or .ent file or the map itself)

remove selected light

save .rtlights file for current level

creates a light with default properties (let there be light!)

toggle on/off the corona option on the selected light

toggle on/off the shadow option on the selected light

unloads GLSL shaders, they will then be reloaded as needed

list all textures used by the current map

override a map texture for testing purposes

restarts renderer
Needs to be done after some changes to the graphic settings.

prints documentation on console commands and variables used by realtime lighting and shadowing system

print information about all loaded textures and some statistics

change your network connection speed

sends a command to the server console (if your rcon_password matches the server's rcon_password), or to the address specified by rcon_address when not connected (again rcon_password must match the server's)

reset signon level in preparation for a new level (do not use)
It DOES NOT reconnect to the last server!

record a demo

restart current level

save the game to a file

save settings to config.cfg immediately (also automatic when quitting)

send a chat message to everyone on the server
bind x "say Hi all. I am going to own you all!!"

send a chat message to your team on the server
bind x "say_team Strength powerup will reappear in 15 Seconds!! Go there now!!"

takes a screenshot of the next rendered frame

sends the value of a cvar to the server as a sentcvar command, for use by QuakeC

create or change the value of a console variable
set variable value
set fov 110 (change your field of view to 110, see fov)

create or change the value of a console variable that will be saved to config.cfg

modifies your userinfo

decrease view size (decreases viewsize cvar)

increase view size (increases viewsize cvar)

downloads missing qw skins from server

reload all sound files

restart sound system

print sound system information (such as channels and speed)

list loaded sounds

signon 2 (client has sent player information, and is asking server to send scoreboard rankings)

start playing back the selected demos sequentially (used at end of startup script)

print server status information

stop recording or playing a demo

stop playing or recording demo (like stop command) and return to looping demos

silence

aborts current upload (screenshot for example)

stop playing a .dpv video file

execute commandline parameters (must be present in quake.rc script)

prints information on culling grid system

save map entities to .ent file (to allow external editing)

send a chat message to only one person on the server

play back a demo as fast as possible and save statistics to benchmark.log

turn quickly and print rendering statistcs

toggles a console variable's values (use for more info)

opens or closes the console

opens or closes menu

QW command to set top color without changing bottom color

removes a command on the specified key in bindmap 0

removes all commands from all keys in all bindmaps (leaving only shift-escape and escape)

prints additional information about a player number or name on the scoreboard

prints additional information about all players on the scoreboard

sets tint color of view

print engine version

restarts video system (closes and reopens the window, restarts renderer)

change animation frame of viewthing entity in current level

change model of viewthing entity in current level

change to next animation frame of viewthing entity in current level

change to previous animation frame of viewthing entity in current level

make script execution wait for next rendered frame
Is necessary in some aliases to work correctly. I.E alias +laser "impulse 1;wait;+fire" alias -laser "-fire"