Change format cells from general to text through command line

Question

[CL]

Hi, Is there a way to convert the format cells of a tab-delimited file (.txt) from "General" to "text" - these are the options that appear if I open this file in excel. However, as it I is quite a big file, I would not like to open it as then when I save it again as text format, not all the data is kept in the file... Is there a way to do that? Or perhaps, to save it already within Rstudio as a text format... Thanks!