All Tcl commands in VMD are composed of one or more words or phrases separated by white space, and terminated by a newline. In Tcl, a ``phrase'' is text surrounded by double quotes or by a matching set of open and close braces. The first word of each command indicates the general purpose for the command, and the following words specify the exact type of command to execute. Table 8.1 summarizes the text commands in VMD by listing the first words, and describing the general purpose for commands starting with those words.
The commands described in the following sections are listed by name, and followed by a list of the available arguments. If an argument is optional, it is enclosed in s. If only one of a list of arguments is needed, the list is enclosed in <>s and the items are separated by |. Words in italics indicate a string or value to be specified by the user.