#!/bin/bash
#
# Sends an ascii-art text file to a parallel port needle/dot-matrix printer.
#
# Usage: ./txt2printr.sh [ascii-art.txt]
# Env:   PRINTER_DEV - printer device node (default: /dev/lp0)

infile="${1:-ascii-img.txt}"
# Source - https://stackoverflow.com/a/638980
# Posted by John Feminella, modified by community. See post 'Timeline' for change history
# Retrieved 2026-07-14, License - CC BY-SA 4.0

if [ -n "$PRINTER_DEV" ]; then
    dev="$PRINTER_DEV"
elif [ -e /dev/lp0 ]; then
    dev=/dev/lp0
elif [ -e /dev/usb/lp0 ]; then
    dev=/dev/usb/lp0
else
    dev=/dev/stdout
fi

if [ ! -f "$infile" ]; then
    echo "txt2printr: file not found: $infile" >&2
    exit 1
fi

if [ ! -w "$dev" ]; then
    echo "txt2printr: cannot write to printer device: $dev" >&2
    echo "txt2printr: set PRINTER_DEV to override, or check permissions/parport module" >&2
    exit 1
fi

{
    printf '\x1b\x40'        # ESC @ - reset printer (ESC/P and IBM Proprinter compatible)
    sed 's/$/\r/' "$infile"  # CRLF line endings, needed for raw writes to avoid staircasing
    printf '\x0c'            # form feed - eject the page
} > "$dev"