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# DHA	12-AUG-2017  (last change)
#
# note that script is called with "bash /...full path .../tr537.sh"
#
# this is DHA's Print Service   (replacing CUPS)
# postscript files $TEFI are automatically sent to the printer using nc (netcat)
#
# note that a PID is allocated for this script before this line is read !!!
FIPI=`pgrep -f "bash /...full path .../tr537.sh"` ; set -- $FIPI
if test $# -gt 1 ; then exit ; fi # do not start script again when logging off/logging on
#
shopt -s dotglob # include hidden files e.g. ".ps"
TEFI=/...full path .../*.ps
while true ; do
    if test -f $TEFI ; then
      sleep 0.2
      nc -w 2 192.***.***.*** 9100 < $TEFI
      zenity --window-icon=/home/...full path .../print.png --notification --timeout=2
      rm -f $TEFI
    fi
  sleep 0.5
done
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SCRIPT COMMENTS
~~~~~~~~~~~~~~~

this "service" is started at logon (or startup/autologon) via
"sys/pref/startup-appl" with "bash /...full path .../tr537.sh <&- &>/dev/null"

calling a script with 'bash x.sh' has some advantages and is clearer than 1.line method

note that this is no genuine Linux service/daemon

the script consumes 2 PIDs per second. I did not find any limitation to this end, patient users may increase 0.5 s to whatever they like, killing the script may leave an orphan

the $TEFI directory is also my sceenshot place but you may define it as part of a RAM disk

the zenity statement presents a printer icon in the panel when transfer to printer is done

note that * is for possible different names of 1 file and NOT for a group of files

the "sleep 0.2" is for the case that the test is applied to an emerging file

note that test -f "$TEFI" results to FALSE in case more than 1 file *.ps would exist ! if, for any reasons, 2 files would exist nothing happens and the number of files not being printed would increase; I did not experience such a case but it may need consideration

all being beyond the features of the normal Print-to-File menu would need scripting effort, i.e.changing y.ps before it is sent to the printer

Of course the script shall not be run under elevated privileges.

FOOTNOTES
~~~~~~~~~

/A/ PCL, HP's Printer Command Languge (versions 1...6) is the de facto industry standard; PCL Technical Reference Manuals are available online

/B/ Brother says 'BR-S3' where 'BR-S3' is footnoted as 'PostScript 3 Emulations'. "LanguageLevel 3" specs are published in a 897 pages Adobe document "PostScript Language Reference third edition" of 1999 (available online)

/C/ having GEDIT open with "x.txt" do file/print/print to file/tick 'Postscript' (Name turns to "x.txt.ps")/set "Save in Folder"/(optionally change "Page Setup" or "Text Editor")/ hit "Print". Now you can open "/.../x.txt.ps" in GEDIT and look at it. Of course you can generate *.ps files from all applications having a print-to-file dialog with the 'Postscript' option. Do not be surprised about the sizes of *.ps files : Even if x.txt would just contain the letter "a" then x.txt.ps is likely more than 10 k caused by the graphical representation. The header of these *.ps files contains "LanguageLevel: 2".

/D/ PPD = PostScript Printer Description File; specs are published in a 236 pages Adobe document "PostScript Printer Description File Format Specification" Version 4.3 of 9 February 1996 (available online)

/E/ Follow CUPS instructions to create a printer 'TEST' using the PPD belonging to your printer (normally published by the vendor) or any modified PPD. Tick "AppSocket/..." and enter as connection : "socket://127.0.0.1:9100" Thus the destination is port 9100 of your own computer and not a network place ! Use nc (=netcat=nc-1.84-24.el6.x86_64=basic repo) from command line 'nc -l 9100 > info.txt'. Now print whatever you want using the printer 'TEST'. The raw data the printer would have received are now in info.txt.