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Manual Pages  — ETDUMP


etdump – Dump El Torito boot catalog information from ISO images



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


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:
  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.


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


The etdump utility first appeared in FreeBSD 11.2

ETDUMP (8) April 25, 2018

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