This command writes the current values of the fit parameters into the given file, formatted as an initial-value file (as described in the fitsection). This is useful for saving the current values for later use or for restarting a converged or stopped fit.
Syntax:
update <filename> {<filename>}
If a second filename is supplied, the updated values are written to this file, and the original parameter file is left unmodified.
Otherwise, if the file already exists, `gnuplot` first renames it by appending `.old` and then opens a new file. That is, "`update 'fred'`" behaves the same as "`!rename fred fred.old; update 'fred.old' 'fred'`". [On DOS and other systems that use the twelve-character "filename.ext" naming convention, "ext" will be "`old`" and "filename" will be related (hopefully recognizably) to the initial name. Renaming is not done at all on VMS systems, since they use file-versioning.]
Please see fit for more information.