What is `bfdname` referred by objcopy manpage?

[PRC]

Hi All,

The manpage of objcopy says:

-O bfdname
--output-target=bfdname
	Write the output file using the object format bfdname.

I have no idea what is bfdname.
Even if I often use `mips-elf-objcopy -O binary a.exe a.bin`, I don't know what is the exact meaning of
-O binary and how many other objects with other bfdnames.

Best regards!

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PanRuochen
2007/09/03