Tail log files and annotate them without affecting them - with screenshots and text - adding context and meaning.

In a nutshell: Print42 is a log tailing GUI program which optionally echoes log lines to thermal printer tape. It features display font size options, search and filtering. You can also annotate the tape with screenshots or text fragments that you type or paste in.

Tail and annotate log files

Programmers can tail log files onto an onscreen virtual tape, which can be annotated without affecting the underlying log file.   Watch the video below to see how useful this is when debugging.

Optionally echo to cheap thermal paper.  Reprint selected text as needed to a thermal printer or to a regular desktop printer.

Search  for important messages. Filter lines with e.g. the word 'error' in them, so that only lines containing that phrase are printed to the on screen tape or thermal printer.

Rapidly print snippets

Print text fragments from the web, screengrabs of long numbers or code fragments, images, or even type your own text line by line.  

Sometimes you just have to print something to study it.

A thermal printer turns on instantly (can be left on & uses no energy till needed), uses no ink and can sit on your desk within easy reach.

Free42 Calculator Support

Echo Free42 (a HP calculator emulator) virtual tape to a real thermal printer! 

Bring back the old days of having a line by line printer tape for your calculator.
Supports both text and GIF image virtual tapes modes, meaning you can plot HP42S graphs.

Fun with thermal paper

Optionally connect a USB thermal printer to your Mac or PC - Print42 will help you get the most out of it. Turn a cheap desktop thermal printer into your productivity companion!

Print black an white photos instantly, create art, have weather reports auto printed every morning - the possibilities are endless!

Potentially leave Print42 running overnight tracking errors lines in a log file. In the morning a programmer, sys admin or programming team can rapidly see and tear off the list of errors that occurred. Like an old fashioned 'ticker tape'

Key Features

Annotate log files - without affecting them

Add screengrabs and text notes to your log files - adding context and meaning

Print42 is a developer tool — a GUI app for tailing log files onto an onscreen printer tape.

The key here is that the onscreen tape is writable, for dumping screenshots and text fragment notes into that same log file tape — without affecting the original log file on disk.

Screenshots and text annotations are inserted into the “tape” and interspersed with the live log file entries. You can then scroll back and see your screenshots and notes and log entries.

In essence you are “annotating” your log file with rich,helpful information — without affecting it, giving context and meaning to points in time in the log file, for more effective subsequent analysis.

Tail log files

View your logfile more conveniently - using different font sizes

Load and monitor any text file, particularly log files which grow in size. Print42 will detect any changes in the log file and display them - scrolling them into view. Known as 'tailing'.

Load and monitor large files. Change font size.

Find text fragments using search.  If you are a programmer you may want to search log files for errors or warnings, or for certain dates when an incident might have occurred.

You can leave printing off, and then select and print the relevant section of of the log file for analysis.  Study the printout with a pen and paper, or stick onto a whiteboard for group discussion.

Optionally, send log file text and images to a thermal or desktop printer.

New in 1.0.2: Filter log files so that only text lines matching your filter appear or get printed to thermal tape.  Great for only printing serious errors from log files - saving paper.  Create a central place in your office where errors get printed onto thermal tape - so that everyone sees errors immediately.  

Rapidly print snippets

Print text and image fragments from the web or your screen

Print text fragments from the web, screengrabs of websites, long numbers or programming code fragments.  Print any images, or even type your own text line by line.

A thermal printer is always silently on, uses no ink and can sit on your desk within easy reach.

You don't even have to print - use Print42 as a 'clipboard' tape of images and text.

Note: Thermal printers are black and white only.  But the virtual tape in Print42 will appear in colour.

"A thermal printer on every programmer's desk.. by the year 2025"

"I believe having a (silent when idle) thermal printer on each programmer's desk is a productivity booster - not just for log files but for printing all sorts of code fragments and screen-grabs that can be written on and studied."

Andy Bulka, Software Developer

Free42 Calculator Support

Echo Free42's virtual tape to a real thermal printer!

Echo Free42 (a cacluator emulator of the classic and much loved HP42S calculator) virtual tape files to a real thermal printer! Bring back the old days of having a line by line printer tape for your calculator, like the the HP 82240B infrared printer.  

Enjoy reliable, blazingly fast printouts without the reliability issues of old second hand HP 82240B prnters from the 80's.  My own 82240B was difficult to purchase and burnt out soon after - read the full story

Great lengths have been taken to support the full character set of the HP42S incl. the characters ▸ ←↑↓→ ≠ ∫∡ etc.

Print42 supports both text and GIF image virtual tapes modes, meaning you can plot HP42S graphs or any output of a HP42S program (via Free42).  

Print42 can auto-detects your Free42 calculator emulator virtual printer tape 'log file' and displays it. Rejoice in the font and image size controls.

HP Prime users: Don't feel left out, use the HP Connectivity Kit to capture screenshots from your HP Prime and print them.  Select the text of your code and print it using Print42's ability to paste and print arbitrary text fragments.  Note: Print42 will wrap long lines.

Why get a thermal printer?

Silent, cheap, fast - and no ink needed!

Receipt printers are FUN. Thermal paper comes on large rolls and lasts ages - and is cheap. No ink needed.

Print black an white photos instantly, create art, have weather reports auto printed every morning - the possibilities are endless!

Thermal printers print line by line - without the "page at a time" metaphor of desktop printing.

Why should retail outlets have all the fun with these fast, fun printers?

Purchase an Epson thermal printer (preferably via our Amazon links at the bottom of our pricing page and plug it in using a USB cable.  Simple.  Installing Print42 will add an additional driver that allows line by line printing controlled by Print42.

Note: Epson's own supplied Mac, Windows and Linux drivers allow regular printing from e.g. MS Word, Pages, Photos etc. further exanding the utility of your new thermal printer.

"A thermal printer based 'ticker tape' for tailing and filtering messages in log files"

One of the fun uses for Print42