strange behavior of "!" symbol

[Bah]

Hi everyone!
I try to get an option in bash and send it to a c program,
like this:
# progName -a "getPacket !MY_IP -> any"
but when I run it, the "!" symbol replace with some strings
that I don't know where are they come from! and this error occurs:
-bash: event not found

then I check this format:
# progName -a "getPacket \!MY_IP -> any"
but I see that "\" pass to my program, too!

I try to do it with double quote option ("!"MY_IP), but it's not
successfully.

Please tell me how can I pass the "!" symbol to my prog?!
(you can run these commands in bash and see one of strange behavior of "!":
pwd !ls
!pwd ls
It seems that "!" points to a temp memory.)

Thank you in advanced.

[Franklin52]

If you want the output of this command as a parameter for your program:

getPacket !MY_IP -> any

try something like:

progName -a `getPacket !MY_IP -> any`

or:

progName -a $(getPacket !MY_IP -> any)

Regards

[Cabhan]

Use single quotes:

alex@danu ~ $ echo !hi
bash: !hi: event not found
alex@danu ~ $ echo "!hi"
bash: !hi: event not found
alex@danu ~ $ echo '!hi'
!hi

What '!' does is it looks for the last command you executed starting with whatever follows '!'. For instance:

alex@danu ~ $ echo "Hello there"
Hello there
alex@danu ~ $ !ec
echo "Hello there"
Hello there

You can also use '!!' to repeat the last command:

alex@danu ~ $ echo "Hello there"
Hello there
alex@danu ~ $ !!
echo "Hello there"
Hello there

I personally use '!' a lot when dealing with mounting:

mount /mnt/usb
# do stuff, not using commands that start with 'mo'
u!mo

That last command will end up as 'umount /mnt/usb'. A much faster way to do that sort of stuff.

'!' has some other cool powers. For instance, '!$' is the last argument of the last command:

alex@danu ~ $ vi testfile1 testfile2
2 files to edit
alex@danu ~ $ echo !$ 
echo testfile2
testfile2

There's a lot of cool stuff that it does.

Sorry for digressing .

[Bah]

OK! it works correctly! Thanks a lot!