When we compile source code, an object file is generated of the program and with the help of linker, this object files gets converted to a binary file which, only the machine can understand. This kind of file follows some structures one of which is ELF(Executable and Linkable Format). And to get the information of these ELF files readelf command is used.
Working with readelf command and ELF files
1. To display help of readelf command.
$readelf
This displays the help section of the command containing all its parameters and their uses. 2. To check whether a file is ELF file.
$file elf_file
If it prints ELF in the output then the file is an ELF file. Note: In our case, file name is elf_file. 3. To generate a elf file using gcc compiler.
$gcc filename.c -o elf_file
The above command will generate an executable elffile. Note: In our case, the name of file is filename.c and the name of elf file is elf_file. 4. To display file headers of a elf file.
$readelf -h elf_file
This will display the top-level headers of the elf file. Note: In our case, the name of elf file is elf_file. 5. To display information about the different sections of the process’ address space.
$readelf -S elf_file
This will display the different sections of the process’ address space. Note: In our case, the name of elf file is elf_file. 6. To display symbols table.
$readelf -s elf_file
This will display the symbols table of the file. Note: In our case, the name of elf file is elf_file. 7. To display core notes.
$readelf -n elf_files
This will display the core notes related to the file. Note: In our case, the name of elf file is elf_file. 8. To display relocation section.
$readelf -r elf_file
This will display the relocks(if present). Note: In our case, the name of elf file is elf_file. 9. To display the dynamic section.
$readelf -d elf_file
This will display the dynamic section of the file. Note: In our case, the name of elf file is elf_file. 10. To get the version of the readelf command.
$readelf -v
This will display the version information of the readelf command.