使用方法：

You can use the commands dump, append, and restore to copy data between target memory and a file. The dump and append commands write data to a file, and the restore command reads data from a file back into the inferior‘s memory. Files may be in binary, Motorola S-record, Intel hex, or Tektronix Hex format; however, gdb can only append to binary files.

dump [format] memory filename start_addr end_addr

dump [format] value filename expr

Dump the contents of memory from start_addr to end_addr, or the value of expr, to filename in the given format.

The format parameter may be any one of:

binary

Raw binary form.

ihex

Intel hex format.

srec

Motorola S-record format.

tekhex

Tektronix Hex format.

gdb uses the same definitions of these formats as the gnu binary utilities, like `objdump‘ and `objcopy‘. If format is omitted, gdb dumps the data in raw binary form.

append [binary] memory filename start_addr end_addr

append [binary] value filename expr

Append the contents of memory from start_addr

to end_addr, or the value of expr, to the file filename, in raw binary form. (gdb can only append data to files in raw binary form.)

restore filename [binary] bias start end

Restore the contents of file filename into memory. The restore command can automatically recognize any known bfd file format, except for raw binary. To restore a raw binary file you must specify the optional keyword binary after the filename.

If bias is non-zero, its value will be added to the addresses contained in the file. Binary files always start at address zero, so they will be restored at address bias. Other bfd files have a built-in location; they will be restored at offset bias from that location.

If start and/or end are non-zero, then only data between file offset start and file offset end will be restored. These offsets are relative to the addresses in the file, before the bias argument is applied.

舉個例子：

dump binary memory result.bin 0x200000000 0x20000c350

This will give you a plain binary dump int file result.bin. You can also use the following to dump it in hex format:

dump ihex memory result.bin 0x200000000 0x20000c350

Using the dump command is much clearer than using the gdb logging hack (which even did not work for me somehow)

參考文檔： https://stackoverflow.com/questions/16095948/gdb-dump-memory-save-formatted-output-into-a-file

GDB dump mem example和命令