$
Means Hex, Memory Lock, List Option, Previous File or End-Of-Line (in Regexp)
Dollar sign is used by Qedit to enable (/$) and disable (/$-) memory lock at the current line.
In the calculator, $ is the prefix for a hexadecimal value (=$FF).
The List command has a variety of temporary options preceded by $. For example:
/list $octal 5/6 {octal dump}
/list $incl abc {Include files}
$ can be used as a shortcut to refer to the "previous" file name referenced in a Qedit command. For example, after List XXX, the $ file name is XXX. If you already have an open workfile or scratch file, a Text or Open command makes Qedit shut the current workfile. Thus, the $ file name now contains the previous workfile name. If you are not using a workfile, then $ is not updated by the Text or Open command. However, it is updated by a Shut command without a file name. You can use $ as a shortcut in commands that refer to an external file name (Open $, Add 1 = $, List $, Use $, etc.). Verify $ shows you the name of the "previous" file.
A dollar sign ($) in regular expressions identifies the end of a line. It takes on this meaning only if it is the last character in the regexp. If used anywhere else in the expression, the dollar sign is used as a literal.
When it represents the end of a line, the dollar sign can find a successful match only when the string is the last thing on a line.
/list "The END$" (regexp) {line must end with "The END"}