Printh

printh( str, [filename,] [overwrite,] [save_to_desktop]  )

Prints a string to a console window that is running PICO-8, or to a file or the clipboard.

str

The string to print.

filename

The name of a file to append the output, instead of printing to the console. If this is the string "@clip", the message replaces the contents of the system clipboard instead of writing to a file.

overwrite

If filename is provided and is the name of a file and overwrite is true, this overwrites the file. The default is false, which appends the message to the end of the file.

save_to_desktop

Create or modify filename on the desktop instead of in Pico-8's data directory.

You can use printh() to emit debugging information without printing it on the PICO-8 display. It can emit this output to a command console window, to a file, or to the system clipboard.

Running PICO-8 in a console window[]

To see the output of printh() in a window, you must run PICO-8 from a command console. How to do this depends on which operating system you're using.

Windows[]

In Windows, instead of double-clicking the PICO-8 icon, open Command Prompt, then start PICO-8 with the following command:

"\Program Files (x86)\PICO-8\pico8.exe"

The prompt appears immediately, even though PICO-8 is running. printh() output will appear in this window anyway.

Alternatively, create a file in the same folder as pico8.exe named pico8.bat containing this line:

cmd /k start pico8.exe

When you double-click on this file, it opens a Command Prompt window and runs PICO-8. Messages appear in the window, and the window closes automatically when PICO-8 exits.

Similar to the above method, you can create a windows shortcut file that launches pico-8 with an attached console; details + video here

Mac OS X[]

In Mac OS X, instead of double-clicking the PICO-8 icon, open Terminal, then start PICO-8 with the following command, adjusting the path to match where you put the app. For example:

/Applications/PICO-8.app/Contents/MacOS/pico8

If you don't want to type that into your terminal every time, you can add an alias to your terminal configuration file. Open a terminal window, and type:

nano ~/.bash_profile

Then, paste the following (do not add any spaces between the = or it will not work!):

alias pico8=/Applications/PICO-8.app/Contents/MacOS/pico8

Save the file, logout and log back in. You will now be able to type pico8 in the terminal to open the program.

Linux[]

In Linux, you probably already run the pico8 command from a terminal window. If you don't, locate where you put the pico-8/ directory, then run the pico8 command from a terminal window using its full path. For example:

~/pico-8/pico8

Writing to a file[]

The printh() function accepts optional arguments that tell it to send its output to a file instead of to the console. This works even if PICO-8 was not invoked from a command console.

To append the message to a file, provide a filename as the second argument. This creates the file if it does not exist.

printh('debug: score='..score, 'scores.txt')

To overwrite an existing file instead of appending to it, provide true as the third argument:

printh('scores', 'scores.txt', true)
printh('------', 'scores.txt')

Writing to the system clipboard[]

Writing to the special filename '@clip', you can overwrite the system clipboard.

See Clipboard for full details.

Examples[]

t = 0

function _update()
  t = (t + 1) % 30
  printh('t = '..t)
end

function _draw()
  cls()
  circfill(t * 3, t * 3, 4, 8)
end