gotoColumn ?-w win? ?col?
If col is specified, the command sets the current position to the given column on the current row and makes it visible. If the value of col is greater than the length of the row, the command jumps to the actual end of the line.
When no col argument is specified, the command is meant for asynchronous use: it prompts for a column in the specified window and jumps to it (equivalent to clicking on the column indicator at the bottom of the window). When run asynchronously, this command returns immediately and should not be used in a Tcl script.