Run PJL Commands From A Shell Script

I love learning obscure and under-utilized things in the tech world; PJL commands fit that bill.  You can use PJL commands to get and set printer preferences.  This includes getting the page count, setting the serial number, and changing the LCD display message.

I was recently tasked with evaluating our printer usage to determine if we could save money by removing low-usage printers.  Like many companies, the majority of our printers were HPs, and we were on a tight budget, so something like Papercut was out of the question.  I also wasn’t about to go around to each printer and print out the usage report, nor did I want to enter the Web interface of every printer to manually get this information.

Thankfully, I had already learned how to use PJL commands to set the serial number.  During that time, I also learned that you could get information from the printer using the INFO command.

There are two parts to this.  First, is a script I made that will accept an IP address as an argument and then use telnet to access the printer, run the PJL command, and then print the output back to the terminal.

The most basic of scripts would look like this:

 { echo -e "\033%-12345X@PJL";
 echo -e @PJL INFO PAGECOUNT;
 echo -e "\033%-12345X";
 sleep 5; } | telnet ${1} 9100 | sed -e 's/\r$//'

This will run the PJL commands using the escape character when you pass an IP address as a first argument to the script.  You could also just replace the ${1} with an IP address, but it’s nice to have it a bit more versatile.

The PJL commands use a special escape character which initially gave me a big headache until I figured out how to enter it on a Mac.  I have learned (thanks to od -bc) that this is just ASCII code 033, so I added that into the script to make it more copy/pasteable.  So the script:

  • echo‘s the commands I want to run
  • pipes them into telnet using the first argument passed to the script–which will be the IP address of the printer–using port 9100
  • removes the carriage return characters via sed
  • sleeps for a few seconds to ensure the output is displayed

This will result in some output like this:

Trying 10.20.10.201...
Connected to someprinter.
Escape character is '^]'.
@PJL INFO PAGECOUNT
3733

I ran this once a month and and then compared the page counts to see how often it was being printed to.

If you wanted to reset the counter to zero after each month, you could also do that by adding in this command:

@PJL SET PAGES=0

In my case, it was more important to know the lifetime usage of the printer since most printers had been around for a decade or more.

4 Replies to “Run PJL Commands From A Shell Script”

  1. Dear Jacob,
    thank you very much for this nice tutorial. Using your example or one containing simply an ECHO ” ” command, I see on my linux console only
    Trying xxx.xxx.xxx.xx….
    Connected to someprinter.
    Escape character is ‘^]’.

    But I never obtain some Information from my OKI-C610dn which should be able to understand basic PJL-Commands too. Any idea?
    Best regards,
    Ludwig

    1. That shows that it is indeed working. So my guess is that the PJL command for getting the information is slightly different. The syntax I use is from some HP documentation, so it may be slightly different for your model printer.

  2. Hello Jacob, great post! I was doing some research into pjl commands. I am a complete noob. I actually work on hardware more than software, repairing printers and such… I can’t find anywhere online where to enter the pjl commands ??? is it in DOS commands? if so how does the printer know you are trying to talk to it? Sorry I am completely new to this. I searched HP and they want you to download a HP web jetadmin software or something like that to manage all your HP printers in one space. Thanks for any help?

    1. My preferred method is using netcat: https://jacobsalmela.com/2015/02/05/change-the-serial-number-on-hp-printers-using-printer-job-language-and-netcat-ftp/

      You can also do it using FTP.

      As long as you are targeting the right printer’s IP address, that’s all you need to know.

      HPs documentation is junk and the most difficult part is determining the escape character. Both this post and the one I linked to should give you enough info to get going.

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