NAME

etdump —

Dump El Torito boot catalog information from ISO images

SYNOPSIS

etdump [-f format] [-o file] file ...

DESCRIPTION

This program reads El Torito boot catalog information from an ISO image and outputs it in various formats. It can be used to check the catalog in an image or to output catalog data in a format that can be used by other tools such as shell scripts.

Supported options are:

-f format --format format

Select the output format. Supported output formats are:

text

Human-readable text (default)

shell

Each boot entry is emitted as a string suitable for passing to a sh-compatible eval command. The variables emitted are:

et_platform: The platform ID from the section header. Set to 'default' for the initial (default) entry.
et_system: The system ID from the boot entry.
et_lba: The starting LBA (2048-byte blocks) of the boot image.
et_sectors: The number of sectors (512-byte sectors) that comprise the boot image.

-o file --output file

Write output to file. If '-' is specified then standard out is used.

EXAMPLES

To see what entries are in a given boot catalog run etdump passing the filename of the image as an argument like so:

% etdump bootonly.iso
Image in bootonly.iso
Default entry
	System i386
	Start LBA 420 (0x1a4), sector count 4 (0x4)
	Media type: no emulation

Section header: efi, final
	Section entry
		System i386
		Start LBA 20 (0x14), sector count 1600 (0x640)
		Media type: no emulation

To use the output in a shell script a for loop can be used to iterate over the entries returned using eval:

for entry in `etdump --format shell bootonly.iso`; do
	eval $entry
	echo $et_platform $et_system $et_lba $et_sectors
done

HISTORY

The etdump utility first appeared in FreeBSD 11.2