Some commands in the game are not words but special characters instead.
For example:

Double quotes (")

Double quotes allow you to view the last 15 lines of conversation on any of the open channels, such as gossip, ooc, hero talk, holler, auction talk, newbie channel, IC. So if you have just logged into the game and you want to know what has been happening on the gossip channel you can type:
"gos

Single quote (')

The single quote mark is an abbreviation for the command SAY, so where you would normally type in:
say Can you give me a million coins?
you can instead type
'Can you give me a million coins?

'Greater then' symbol (>)

The greater then symbol, or pointy right bracket, is an abbreviation of the sayto command, so where you would normally type in:
sayto mordecai I finished that quest you gave me.
you can instead type
>mordecai I finished that quest you gave me.

Period (.)

The period is an abbreviation for the gossip channel, considering how frequently the gossip channel is used by most players it is helpful to not have to type gossip, or even gos
gossip Hey, you Elves are going down.
you can instead type
.Hey, You Elves are going down.

Colon (:)

The colon is an abbreviation for the emote command, also a frequently typed command by many players.
emote plunges his hand into your chest and rips out your spine.
you can instead type
:plunges his hand into your chest and rips out your spine.

This also works for plural emotes.
:'s face is on fire.
would display
Mordecai's face is on fire.

Double hyphen (--)

The double hyphen is a special command. Many commands come with a certain delay after them. For example when you use the skill kick. You get about a 2 second delay before your next command gets processed. Same with quaffing potions.
So imagine you are fighting a large gang leader, or a space cop. You start the fight and you don't want to die so you send through 'quaff potion' 40 or so times. Somehow you kill the gang leader after only 12 potions. Normally even after the fight has ended, your player will stand there and finish quaffing the left over 28 potions before you can do anything else.
That is when you use the double hyphen. That will clear all of your pending commands. So you can get on with what you are doing.

Carat (^)

This is another special command. It allows you to redo your last command with a replacement word or phrase.
used like this
^pattern^replacement
For example if I typed:
get apple from green bag
And i also wanted the orange, i could type
^apple^orange
It would send through the command
get orange from green bag

This is especially useful when you typo a word in a sentence that needs to be typed exactly for a quest for example.
say I went down teh rode and fetched you your rabbit fur slippers!
^teh rode^the road

Exclamation (!)

The last 5 commands you type are kept, and using the ! command you can recall what that command was and issue it again.
for example, if I type:
get gold from corpse
drop 200 coin
west

If i wanted to do the get gold from corpse command again, i could just type:
!get g
or even just
!ge
Then to drop 200 coins again.
!drop 200
or just
!dr

To recall the very last command I did, I can just type:
!

For example, I may want to:
quaff green sparkling potion
then instead of typing that out again and again, just use the ! command.

I hope this helps!
Mordecai