The GNU objcopy utility copies the contents of an object file to another. objcopy uses the GNU BFD Library to read and write the object files. It can write the destination object file in a format different from that of the source object file. The exact behavior of objcopy is controlled by command-line options.

objcopy creates temporary files to do its translations and deletes them afterward. objcopy uses BFD to do all its translation work; it has access to all the formats described in BFD and thus is able to recognize most formats without being told explicitly. See BFD in Using ld.

objcopy can be used to generate S-records by using an output target of ‘srec’ (e.g., use ‘-Osrec’).

objcopy can be used to generate a raw binary file by using an output target of ‘binary’ (e.g., use ‘-Obinary’). When objcopy generates a raw binary file, it will essentially produce a memory dump of the contents of the input object file. All symbols and relocation information will be discarded. The memory dump will start at the virtual address of the lowest section copied into the output file.

When generating an S-record or a raw binary file, it may be helpful to use -S to remove sections containing debugging information. In some cases ‘-R’ will be useful to remove sections which contain information which is not needed by the binary file.
 

infile
outfile
The source and output files, respectively. If you do not specify outfile, objcopy creates a temporary file and destructively renames the result with the name of infile.
-Ibfdname
--input-target=bfdname
Consider the source file’s object format to be bfdname, rather than attempting to deduce it. See Target selection for more information.
-Obfdname
--output-target=bfdname
Write the output file using the object format bfdname. See Target selection for more information.
-F bfdname
--target=bfdname
Use bfdname as the object format for both the input and the output file; i.e., simply transfer data from source to destination with no translation. See Target selection for more information.
-R sectionname
--remove-section=sectionname
Remove any section named sectionname from the output file. This option may be given more than once.
Note:
Using this option inappropriately may make the output file unusable.
-S
--strip-all
Do not copy relocation and symbol information from the source file.
-g
--strip-debug
Do not copy debugging symbols from the source file.
--strip-unneeded
Strip all symbols that are not needed for relocation processing.
-K symbolname
--keep-symbol=symbolname
Copy only symbol symbolname from the source file. This option may be given more than once.
-N symbolname
--strip-symbol=symbolname
Do not copy symbol symbolname from the source file. This option may be given more than once, and may be combined with strip options other than -K.
-x
--discard-all
Do not copy non-global symbols from the source file.
-X
--discard-locals
Do not copy compiler-generated local symbols. (These usually start with ‘L’ or ‘.’.)
-b byte
--byte=byte
Keep only every byteth byte of the input file (header data is not affected). byte can be in the range from 0 to interleave-1, where interleave is given by the ‘-i’ or ‘--interleave’ option, or the default of 4. This option is useful for creating files to program ROM . It is typically used with an srec output target.
-i interleave
--interleave=interleave
Only copy one out of every interleave bytes. Select which byte to copy with the ‘-b’ or ‘--byte’ option. The default is 4. objcopy ignores this option if you do not specify either ‘-b’ or ‘--byte’.
--debugging
Convert debugging information, if possible. This is not the default because only certain debugging formats are supported, and the conversion process can be time consuming.
--gap-fill val
Fill gaps between sections with val. This is done by increasing the size of the section with the lower address, and filling in the extra space created with val.
--pad-to address
Pad the output file up to the virtual address, address. This is done by increasing the size of the last section. The extra space is filled in with the value specified by ‘--gap-fill’ (default zero).
--set-start val
Set the address of the new file to val. Not all object file formats support setting the start address.
--adjust-start incr
Adjust the start address by adding incr. Not all object file formats support setting the start address.
--adjust-vma incr
Adjust the address of all sections, as well as the start address, by adding incr. Some object file formats do not permit section addresses to be changed arbitrarily. Note that this does not relocate the sections; if the program expects sections to be loaded at a certain address, and this option is used to change the sections such that they are loaded at a different address, the program may fail.
--adjust-section-vma section{=,+,-}val
Set or adjust the address of the named section. If ‘=’ is used, the section address is set to val. Otherwise, val is added to or subtracted from the section address. See the comments under ‘--adjust-vma’. If section does not exist in the input file, a warning will be issued, unless ‘--no-adjust-warnings’ is used.
--adjust-warnings
If ‘--adjust-section-vma’ is used, and the named section does not exist, issue a warning. This is the default.
--no-adjust-warnings
Do not issue a warning if ‘--adjust-section-vma’ is used, even if the named section does not exist.
--set-section-flags section=flags
Set the flags for the named section. The flags argument is a comma separated string of flag names. The recognized names are ‘alloc’, ‘load’, ‘readonly’, ‘code’, ‘data’, and ‘rom’. Not all flags are meaningful for all object file formats.
--add-section sectionname=filename
Add a new section named sectionname while copying the file. The contents of the new section are taken from the file filename. The size of the section will be the size of the file. This option only works on file formats which can support sections with arbitrary names.
--remove-leading-char
If the first character of a global symbol is a special symbol leading character used by the object file format, remove the character. The most common symbol leading character is underscore. This option will remove a leading underscore from all global symbols. This can be useful if you want to link together objects of different file formats with different conventions for symbol names.
-V
--version
Show the version number of objcopy.
-v
--verbose
Verbose output: list all object files modified. In the case of archives, ‘objcopy -V’ lists all members of the archive.
--help
Show a summary of the options to objcopy.