showfont

showfont [ -display display ] [ -pixmap ] [ -x ] [ -y ] [ -lsb ] [ -msb ] [ fontname ]

-display display
    Specifies the X server to connect to. This allows displaying fonts on a remote machine's display.

-pixmap
    Forces the output to be drawn into a pixmap first, then copied to the window. This can be useful for improving performance over slow network connections or for certain display configurations.

-x
    Arranges the characters horizontally across the display window. This is typically the default behavior.

-y
    Arranges the characters vertically down the display window, displaying one character per line.

-lsb
    Sets the bit order for the font data to Least Significant Bit (LSB) first. This controls how the individual bits within a byte are interpreted for the bitmap.

-msb
    Sets the bit order for the font data to Most Significant Bit (MSB) first. This is the common default for most systems.

fontname
    The path and name of the font file to be displayed. This is typically a BDF file, but can also be PCF or SNF.

The showfont command is a utility within the X Window System used to display the characters contained within a font file on an X server. It primarily supports bitmap font formats such as BDF (Bitmap Distribution Format), PCF (Portable Compiled Format), and SNF (Server Natural Format). This tool is invaluable for font developers, designers, or anyone needing to visually inspect the actual bitmap representation of characters, including their metrics, bounding boxes, and glyphs. By providing a direct visual output, showfont helps in debugging font issues, verifying character design, or simply exploring the content of a font file before it is installed or used by applications. It offers options to control the display orientation (horizontal or vertical) and bit order, making it flexible for various inspection needs.

showfont requires an active X Window System display to operate, as it directly renders font bitmaps to an X server window.
It is primarily designed for static bitmap fonts (BDF, PCF, SNF) and does not directly support scalable font formats like TrueType or OpenType, which are more common today.
Performance can be an issue over slow network connections without the use of the -pixmap option.

showfont is specifically designed to work with traditional X11 bitmap font formats, including BDF (Bitmap Distribution Format), PCF (Portable Compiled Format), and SNF (Server Natural Format). It does not directly render scalable outline fonts.

showfont has been a part of the X Window System distribution for a long time, originating from the early days of X11 development. It was particularly relevant when bitmap fonts were the dominant font technology on X servers. While modern systems increasingly rely on scalable font technologies (like TrueType and OpenType via Fontconfig and FreeType), showfont remains a useful diagnostic and inspection tool for older font assets or for understanding bitmap font structures.

xlsfonts(1), xfd(1), xset(1), bdftopcf(1), mkfontdir(1)