Ghostscript Combine ps with pdf file and add the first line (header) - pdf

Question

I need to combine ps with pdf file and add the first line "#S Company Name" for the combined file.
I use the command:
gswin64c.exe -o combine.ps -sDEVICE=ps2write -f fax003.ps -f warning.pdf
How can I add an extra line "#S Company Name" to the output file combine.ps?
Should get such a file:
#S Company Name **-- first line--**
%!PS-Adobe-3.0
%%BoundingBox: 0 0 595 842
%%HiResBoundingBox: 0 0 595.00 842.00
%%Creator: GPL Ghostscript 922 (ps2write)
%%LanguageLevel: 2
%%CreationDate: D:20180304115454+02'00'
%%Pages: 13
%%EndComments
%%BeginProlog
/DSC_OPDFREAD true def
/SetPageSize true def
/EPS2Write false def
currentdict/DSC_OPDFREAD known{
currentdict/DSC_OPDFREAD get
}{
false
}ifelse
10 dict begin
/DSC_OPDFREAD exch def
/this currentdict def
...

Answer 1

What you've written as the output file is not valid PostScript. The presence of the "#5...." text will cause a PostScript interpreter to throw an error.
So, assuming that you have a workflow where this will be stripped off. You can't do exactly this with an unmodified Ghostscript. Your only solution will be to open the file after it has been completely output and modify it. Or, of course, alter the pdfwrite device source code and rebuild the Ghostscript executable.
Since you appear to be using Ghostscript in a commercial environment, can I just draw your attention to the licence under which it is supplied; this is the AGPL v3, which covers usage such as Software-as-a-Service. I don't want you to think I'm accusing you of using Ghostscript other than in accordance with the terms of the licence, I just want to make certain you are aware of the terms.