fbgrab

capture framebuffer screenshots to PNG

TLDR

Take a screenshot of the current framebuffer

$ fbgrab [screenshot.png]

Take a screenshot from a specific framebuffer device

$ fbgrab -d [/dev/fb1] [screenshot.png]

Take a screenshot of a specific virtual console

$ fbgrab -c [1] [screenshot.png]

Wait 5 seconds before taking a screenshot

$ fbgrab -s [5] [screenshot.png]

Convert a raw framebuffer dump to PNG

$ fbgrab -w [1920] -h [1080] -b [32] -f [framebuffer.dump] [screenshot.png]

Set PNG compression level (0=fast, 9=best)

$ fbgrab -z [9] [screenshot.png]

fbgrab reads the Linux framebuffer device (/dev/fb*) or a dump thereof and saves a PNG image file. It can capture screenshots of virtually any application, from traditional text applications to X-windows desktops and framebuffer applications.The tool is particularly useful for capturing screenshots on systems without a running X server, embedded systems, or when working directly with the Linux console.

PARAMETERS

Display usage information.

-a

Ignore the alpha channel. Useful for pixel formats like BGR32 where drivers incorrectly report alpha.

-b bitdepth

The number of bits per pixel. Optional when reading from device.

-c console

Specifies which console (virtual terminal) to grab.

-C console

Switch console with a delay before capturing.

-d device

Framebuffer device to use. Defaults to FRAMEBUFFER environment variable or /dev/fb0.

-f filename

Read from file instead of device. Requires -w, -h, and -b options.

-h height

The height of the framebuffer in pixels. Optional when reading from device.

-i

Turns off ADAM7 interlacing in the output PNG.

-l linelength_

Line length (stride) in pixels between the start of each row. Optional when reading from device.

-s seconds

Seconds to wait before grabbing the screenshot.

-v

Enable verbose output.

-w width

The width of the framebuffer in pixels. Optional when reading from device.

-z compression

Set PNG compression level (0=fast, 9=best).

INSTALL

sudo apt install fbcat

sudo pacman -S fbgrab

sudo apk add fbgrab

sudo zypper install fbcat

nix profile install nixpkgs#fbcat

CAVEATS

The -c option may require root privileges or the CAPSYSTTY_CONFIG capability. When reading from a raw dump file, the -w, -h, and -b options must all be specified. The framebuffer device must be accessible with appropriate permissions.

HISTORY

fbgrab was written by Gunnar Monell as a rewrite of fbshot by Stephan Beyer. The tool has been maintained since 2002 and is licensed under GPL version 2.