The DIRCMD variable is used by some versions of CMD to hold default options for the DIR command. TCC does not directly support this variable, i.e, its value has no affect on internal commands. In general, it is more efficient to define several aliases, each including a different combination of options. For example, if you want the DIR command to default to a 2-column display with a vertical sort and a pause at the end of each page, you could use this alias:
alias DIR=`*dir /2 /p /v`I
If you wish to use or create a DIRCMD variable for compatibility with CMD, you can define the alias to append the contents of that variable to the DIR command:
alias DIR=`*dir %dircmd`
Now each time the DIR alias is executed, the current value of DIRCMD will modify the execution of the DIR command.