Shell Programming and Scripting

Hi,

I'm new to this and very much interested to learn unix.
Can any one explain me the symbols y we use this is scripting(~ and $).
It would be great if some one explain with the eg.

Thanks
Naveen A

$ is used to access (read) a variable. Whenever you see $ symbol, whatever follows is a shell variable.

So look at the following:

Code:

x=12 # assigns value of 12 to the variable "x"
echo $x # reads variable "x", gets value of 12, echo command prints 12

Alternatively, you can say ${x} which is exactly the same. This can be used to prevent the letter x from "running into" other following text.

Of course, when you are using UNIX at the command line, $ is the typical command prompt.

Naveen,
I think hanson44 pretty well described many of the uses of $. The $ is also used to represent the end of a string in a regular expression and can actually be used to represent the dollar sign symbol in a string (depending on context and they types of quotes used to delimit the string).

The ~ is used to represent a user's home directory when it is unquoted at the start of a pathname. It can be used by itself to represent the home directory of the user who is currently logged in (such as vi ~/.profile to edit a file named .profile in your home directory) or with a user's name to represent that user's home directory (such as vi ~dwc/.profile to try to edit the file named .profile in my home directory).