A command in the TclX package.
The lvarpush command pushes (inserts) string as an element in the list contained in the variable var. The element is inserted before position indexExpr in the list. If indexExpr is omitted, then 0 is assumed. If var does not exist, it is created.
If the expression indexExpr starts with the string "end", then end is replaced with the index of the last element in the list. If the expression starts with "len", then len is replaced with the length of the list. Note the value of "end" means insert the string before the last element.
See also lvarpop.