These comments ensure that the postscript program enclosed in these comment lines can be exchanged between different graphics programs in a hardware-independent manner. EPS files, which are normally generated by graphics applications for prepress, usually do not contain loops or logical conditions. These are practically the additional possibilities available in Postscript programming.
The EPS format was developed to achieve interchangeability between different programs. Because Postscript does not require a mandatory structure, thus leaving the programmer a certain freedom in creating the source code, the actual content of the program, e.g. in terms of the space required for the generated page or the fonts used, can only be found out with a good knowledge of the Postscript language.
The file extension for EPS files is *.eps.