Other ExcelTips have discussed opening, reading, writing, appending, and closing text files. Another VBA function associated with sequential text files is the LOF function. If used on an open file, it returns the length of the file, in bytes. In other words, you can determine the number of characters in the file.
This can come in handy if you are processing a text file character by character. You can determine the length of the file and then read that many characters before you finish processing the file. The following code fragment is an example of how the LOF function is used:
Open "MyFile.Dat" for Input as #1 FileLen = LOF(1)