Write a figure to a file automatically in MATLAB

This was answered in this other question, using the PRINT command. Although that question dealt with making .tiff images, it should be straightforward to modify the code given in those answers to write a .eps.

print or saveas will do the trick.

saveas(fig_handle, 'filename','eps')
print('-deps',fig_handle)
print -deps 1

If you want to specify the output file name, you're better off using saveas.

print function does that:

Print figure or save to specific file format...

print(filename,formattype) saves the current figure to a file using the specified file format, such as print('BarPlot','-dpng'). If the file name does not include an extension, then print appends the appropriate one.

print(filename,formattype,formatoptions) specifies additional options that are available for some formats.

print prints the current figure to the default printer...