OBJDUMP(1)

okay so this is OBJDUMP(1) from the GNU Development Tools manual, and bestie, we're about to spill all the tea ☕️ Part 1 of 4, so stay tuned.

✨ NAME ✨

objdump — it literally displays information from object files, periodt.

📜 SYNOPSIS 📜

       objdump [-a|--archive-headers]
               [-b bfdname|--target=bfdname]
               [-C|--demangle[=style] ]
               [-d|--disassemble[=symbol]]
               [-D|--disassemble-all]
               [-z|--disassemble-zeroes]
               [-EB|-EL|--endian={big | little }]
               [-f|--file-headers]
               [-F|--file-offsets]
               [--file-start-context]
               [-g|--debugging]
               [-e|--debugging-tags]
               [-h|--section-headers|--headers]
               [-i|--info]
               [-j section|--section=section]
               [-l|--line-numbers]
               [-S|--source]
               [--source-comment[=text]]
               [-m machine|--architecture=machine]
               [-M options|--disassembler-options=options]
               [-p|--private-headers]
               [-P options|--private=options]
               [-r|--reloc]
               [-R|--dynamic-reloc]
               [-s|--full-contents]
               [-Z|--decompress]
               [-W|--dwarf]
               [-Wa|--dwarf=abbrev]
               [-WA|--dwarf=addr]
               [-Wr|--dwarf=aranges]
               [-Wc|--dwarf=cu_index]
               [-WL|--dwarf=decodedline]
               [-Wf|--dwarf=frames]
               [-WF|--dwarf=frames-interp]
               [-Wg|--dwarf=gdb_index]
               [-Wi|--dwarf=info]
               [-Wk|--dwarf=links]
               [-Wo|--dwarf=loc]
               [-Wm|--dwarf=macro]
               [-Wp|--dwarf=pubnames]
               [-Wt|--dwarf=pubtypes]
               [-WR|--dwarf=Ranges]
               [-Wl|--dwarf=rawline]
               [-Ws|--dwarf=str]
               [-WO|--dwarf=str-offsets]
               [-Wu|--dwarf=trace_abbrev]
               [-WT|--dwarf=trace_aranges]
               [-WU|--dwarf=trace_info]
               [-WK|--dwarf=follow-links]
               [-WN|--dwarf=no-follow-links]
               [-WD|--dwarf=use-debuginfod]
               [-WE|--dwarf=do-not-use-debuginfod]
               [--debug-dir=dir]
               [--map-global-vars]
               [-L|--process-links]
               [--ctf=section]
               [--sframe=section]
               [-G|--stabs]
               [-t|--syms]
               [-T|--dynamic-syms]
               [-x|--all-headers]
               [-w|--wide]
               [--start-address=address]
               [--stop-address=address]
               [--no-addresses]
               [--prefix-addresses]
               [--[no-]show-raw-insn]
               [--adjust-vma=offset]
               [--show-all-symbols]
               [--dwarf-depth=n]
               [--dwarf-start=n]
               [--ctf-parent=section]
               [--no-recurse-limit|--recurse-limit]
               [--special-syms]
               [--prefix=prefix]
               [--prefix-strip=level]
               [--insn-width=width]
               [--visualize-jumps[=color|=extended-color|=off]
               [--disassembler-color=[off|terminal|on|extended]
               [-U method] [--unicode=method]
               [-V|--version]
               [-H|--help]
               objfile...

📖 DESCRIPTION 📖

So basically, objdump shows you information about one or more object files. The options control exactly what info gets displayed. This stuff is mostly useful for programmers working on the compilation tools, not just for programmers who want their program to compile and work.

objfile... are the object files you wanna examine. When you specify archives, objdump shows info on each of the member object files.

⚙️ OPTIONS ⚙️

The long and short forms of options, shown here as alternatives, are equivalent. You gotta give at least one option from this list: -a,-d,-D,-e,-f,-g,-G,-h,-H,-p,-P,-r,-R,-s,-S,-t,-T,-V,-x.

• -a, --archive-header — If any of the objfile files are archives, this spills the archive header info (in a format similar to ls -l). Besides the info you could list with ar tv, objdump -a also shows the object file format of each archive member. Iconic.
• --adjust-vma=offset — When dumping info, first add offset to all the section addresses. This is useful if the section addresses don't correspond to the symbol table, which can happen when you put sections at particular addresses using a format that can't represent section addresses, like a.out. Periodt.
• -b bfdname, --target=bfdname — Specify that the object-code format for the object files is bfdname. This option may not be necessary; objdump can automatically recognize many formats. For example,

objdump -b oasys -m vax -h fu.o

displays summary info from the section headers (-h) of fu.o, which is explicitly identified (-m) as a VAX object file in the format produced by Oasys compilers. You can list the formats available with the -i option. Slay.

• -C, --demangle[=style] — Decode (demangle) low-level symbol names into user-level names. Besides removing any initial underscore prepended by the system, this makes C++ function names readable. Different compilers have different mangling styles. The optional style argument can be used to choose an appropriate demangling style for your compiler. Bestie, it's giving readability.
• --recurse-limit, --no-recurse-limit, --recursion-limit, --no-recursion-limit — Enables or disables a limit on the amount of recursion performed whilst demangling strings. Since the name mangling formats allow for an infinite level of recursion, it's possible to create strings whose decoding will exhaust the stack space available on the host machine, triggering a memory fault. The limit tries to prevent this by restricting recursion to 2048 levels of nesting. The default is for this limit to be enabled, but disabling it may be necessary in order to demangle truly complicated names. Note however that if the recursion limit is disabled then stack exhaustion is possible and any bug reports about such an event will be rejected. So be careful, bestie.
• -g, --debugging — Display debugging information. This attempts to parse STABS debugging format information stored in the file and print it out using a C-like syntax. If no STABS debugging was found, this option falls back on the -W option to print any DWARF information in the file. Versatile.
• -e, --debugging-tags — Like -g, but the info is generated in a format compatible with the ctags tool. Cute.
• -d, --disassemble, --disassemble=symbol — Display the assembler mnemonics for the machine instructions from the input file. This option only disassembles those sections which are expected to contain instructions. If the optional symbol argument is given (perhaps multiple times), then display the assembler mnemonics starting at (all the) symbol. If symbol is a function name then disassembly will stop at the end of the function, otherwise it will stop when the next symbol is encountered. If there are no matches for any symbol then nothing will be displayed. Note: if the --dwarf=follow-links option is enabled, then any symbol tables in linked debug info files will be read in and used when disassembling. Slay.
• -D, --disassemble-all — Like -d, but disassemble the contents of all non-empty non-bss sections, not just those expected to contain instructions. -j may be used to select specific sections. This option also has a subtle effect on the disassembly of instructions in code sections. When option -d is in effect, objdump will assume that any symbols present in a code section occur on the boundary between instructions and it will refuse to disassemble across such a boundary. When option -D is in effect however, this assumption is suppressed. This means that it's possible for the output of -d and -D to differ if, for example, data is stored in code sections. If the target is an ARM architecture, this switch also has the effect of forcing the disassembler to decode pieces of data found in code sections as if they were instructions. Note: if the --dwarf=follow-links option is enabled, then any symbol tables in linked debug info files will be read in and used when disassembling. Wild.
• --no-addresses — When disassembling, don't print addresses on each line or for symbols and relocation offsets. In combination with --no-show-raw-insn this may be useful for comparing compiler output. Periodt.
• --prefix-addresses — When disassembling, print the complete address on each line. This is the older disassembly format. Nostalgic.
• -EB, -EL, --endian={big|little} — Specify the endianness of the object files. This only affects disassembly. This can be useful when disassembling a file format which does not describe endianness information, such as S-records. Because sometimes you gotta specify.
• -f, --file-headers — Display summary information from the overall header of each of the objfile files. Big picture energy.
• -F, --file-offsets — When disassembling sections, whenever a symbol is displayed, also display the file offset of the region of data that is about to be dumped. If zeroes are being skipped, then when disassembly resumes, tell the user how many zeroes were skipped and the file offset of the location from where the disassembly resumes. When dumping sections, display the file offset of the location from where the dump starts. So you're never lost.
• --file-start-context — Specify that when displaying interlisted source code/disassembly (assumes -S) from a file that has not yet been displayed, extend the context to the start of the file. Full picture, bestie.
• -h, --section-headers, --headers — Display summary information from the section headers of the object file. File segments may be relocated to nonstandard addresses, for example by using the -Ttext, -Tdata, or -Tbss options to ld. However, some object file formats, such as a.out, do not store the starting address of the file segments. In those situations, although ld relocates the sections correctly, using objdump -h to list the file section headers cannot show the correct addresses. Instead, it shows the usual addresses, which are implicit for the target. Note: in some cases it is possible for a section to have both the READONLY and the NOREAD attributes set. In such cases the NOREAD attribute takes precedence, but objdump will report both since the exact setting of the flag bits might be important. The more you know.
• -H, --help — Print a summary of the options to objdump and exit. Simple.
• -i, --info — Display a list showing all architectures and object formats available for specification with -b or -m. So you know what's on the menu.

---

✨ part 2 coming soon, bestie ✨

• -j name, --section=name — shows you the info for a section called name, and bestie you can stack this — specify it as many times as you want. 💅
• --map-global-vars — spills all the global variable info 📋 and heads up, it only does anything when the object file was compiled with the debug option. More precisely, it relies on DWARF2 debug information entries. It's the move for tracking the location and type of literally every global variable in the object file you gave it. 🔎
• -L, --process-links — displays the contents of non-debug sections found in separate debuginfo files that are linked to the main file. This option automatically implies the -WK option ✨, and only sections requested by other command line options will actually get displayed.
• -l, --line-numbers — labels the display with the filename and source line numbers that correspond to the object code or relocs shown (using debugging information, ofc). Only useful with -d, -D, or -r. Not me telling you twice. 👀
• -m machine, --architecture=machine — specifies the architecture to use when disassembling object files. So useful when the object files don't describe any architecture info, like S-records. You can list the available architectures with the -i option. 🌈

For most architectures you can hmu with an architecture name and a machine name separated by a colon. So like foo:bar would refer to the bar machine type in the foo architecture. Super helpful if objdump has been configured to support multiple architectures. 💖

If the target is an ARM architecture then this switch has an extra lil side effect: it restricts the disassembly to only those instructions supported by the architecture specified in machine. And if you gotta use this switch because the input file has no architecture information, but you also wanna disassemble all the instructions, use -marm. periodt.

• -M options, --disassembler-options=options — passes target specific info to the disassembler. Only supported on some targets, no cap. Need more than one disassembler option? Either use multiple -M options or put them all together into a comma separated list. 🎀

ARC 🦋 — dsp controls the printing of DSP instructions, spfp selects the printing of FPX single precision FP instructions, dpfp selects the printing of FPX double precision FP instructions, quarkse_em selects the printing of special QuarkSE-EM instructions, fpuda selects the printing of double precision assist instructions, fpus selects the printing of FPU single precision FP instructions, while fpud selects the printing of FPU double precision FP instructions. And you can also choose to have all the immediates printed in hexadecimal using hex — by default, the short immediates are printed using the decimal representation, while the long immediate values are printed as hexadecimal.

cpu=... lets you enforce a particular ISA when disassembling instructions, overriding the -m value or whatever's sitting in the ELF file. This might be useful to select ARC EM or HS ISA, because the architecture is the same for those and the disassembler relies on private ELF header data to decide if the code is for EM or HS. You can specify this option multiple times — only the latest value will be used. Valid values are the same as for the assembler -mcpu=... option.

ARM 💜 — for an ARM architecture this switch can select which register name set is used during disassembly. Specifying -M reg-names-std (the default) will select the register names as used in ARM's instruction set documentation, but with register 13 called sp, register 14 called lr and register 15 called pc. Specifying -M reg-names-apcs will select the name set used by the ARM Procedure Call Standard, whilst specifying -M reg-names-raw will just use r followed by the register number.

There are also two variants on the APCS register naming scheme, enabled by -M reg-names-atpcs and -M reg-names-special-atpcs, which use the ARM/Thumb Procedure Call Standard naming conventions. (Either with the normal register names or the special register names. 💁)

This option can also be used for ARM architectures to force the disassembler to interpret all instructions as Thumb instructions, by using the switch --disassembler-options=force-thumb. This can be useful when you're attempting to disassemble thumb code produced by other compilers.

AArch64 🌸 — this switch can be used to set whether instructions are disassembled as the most general instruction using the -M no-aliases option, or whether instruction notes should be generated as comments in the disassembly using -M notes. In addition, the -M annotate option customises the handling of undefined instructions when disassembling executables and shared libraries. Normally the disassembler will just show the hexadecimal value of the undefined instruction, but if annotation is enabled it will first try to find a symbol whose value matches the instruction's encoding. If there's a match, then the symbol name gets displayed instead. This can be useful when disassembling non-code sections which may contain function and data addresses.

x86 — some of these options duplicate functions of the -m switch, but allow finer grained control:

• x86-64, i386, i8086 — Select disassembly for the given architecture.
• intel, att — Select between intel syntax mode and AT&T syntax mode.
• amd64, intel64 — Select between AMD64 ISA and Intel64 ISA.
• intel-mnemonic, att-mnemonic — Select between intel mnemonic mode and AT&T mnemonic mode. Note: intel-mnemonic implies intel and att-mnemonic implies att.
• addr64, addr32, addr16, data32, data16 — Specify the default address size and operand size. These five options will be overridden if x86-64, i386 or i8086 appear later in the option string.
• suffix — When in AT&T mode and also for a limited set of instructions when in Intel mode, instructs the disassembler to print a mnemonic suffix even when the suffix could be inferred by the operands or, for certain instructions, the execution mode's defaults.
• annotate-immediates — Display the symbol associated with immediate values, should there be one. Only works on executable binaries and shared libraries, not static object files.

PowerPC 🔥 — the -M argument raw selects disassembly of hardware insns rather than aliases. So for example you'll see rlwinm rather than clrlwi, and addi rather than li. All of the -m arguments for gas that select a CPU are supported. These are: 403, 405, 440, 464, 476, 601, 603, 604, 620, 7400, 7410, 7450, 7455, 750cl, 821, 850, 860, a2, booke, booke32, cell, com, e200z2, e200z4, e300, e500, e500mc, e500mc64, e500x2, e5500, e6500, efs, power4, power5, power6, power7, power8, power9, power10, power11, ppc, ppc32, ppc64, ppc64bridge, ppcps, pwr, pwr2, pwr4, pwr5, pwr5x, pwr6, pwr7, pwr8, pwr9, pwr10, pwr11, pwrx, titan, vle, and future. 32 and 64 modify the default or a prior CPU selection, disabling and enabling 64-bit insns respectively. In addition, altivec, any, lsp, htm, vsx, spe and spe2 add capabilities to a previous or later CPU selection. any will disassemble any opcode known to binutils, but in cases where an opcode has two different meanings or different arguments, you may not see the disassembly you expect. And if you disassemble without giving a CPU selection, a default will be chosen from information gleaned by BFD from the object file headers, but the result again may not be as you expect. 😭

RISC-V 🧚 — the following options are supported:

• max — Disassemble without checking architecture string. This is a best effort mode, so for overlapping ISA extensions the first match (possibly incorrect in a given context) will be used to decode the instruction. It's useful if the ELF file doesn't expose ISA string, preventing automatic ISA subset deduction, and the default fallback ISA string (rv64gc) doesn't cover all instructions in the binary.
• numeric — Print numeric register names, rather than ABI names (e.g., print x2 instead of sp).
• no-aliases — Disassemble only into canonical instructions. For example, compressed instructions will be represented as such (addi sp,sp,-128 will be c.addi16sp sp,-128).
• priv-spec=SPEC — Print the CSR according to the chosen privilege spec version (e.g., 1.10, 1.11, 1.12, 1.13).

MIPS 💫 — for MIPS, this option controls the printing of instruction mnemonic names and register names in disassembled instructions. Multiple selections from the following may be specified as a comma separated string, and invalid options are ignored:

• no-aliases — Print the 'raw' instruction mnemonic instead of some pseudo instruction mnemonic. I.e., print daddu or or instead of move, sll instead of nop, etc.
• msa — Disassemble MSA instructions.
• virt — Disassemble the virtualization ASE instructions.
• xpa — Disassemble the eXtended Physical Address (XPA) ASE instructions.
• gpr-names=ABI — Print GPR (general-purpose register) names as appropriate for the specified ABI. By default, GPR names are selected according to the ABI of the binary being disassembled.
• fpr-names=ABI — Print FPR (floating-point register) names as appropriate for the specified ABI. By default, FPR numbers are printed rather than names.
• cp0-names=ARCH — Print CP0 (system control coprocessor; coprocessor 0) register names as appropriate for the CPU or architecture specified by ARCH. By default, CP0 register names are selected according to the architecture and CPU of the binary being disassembled.

Continuing the -M machine options because we are ✨not done✨:

• hwr-names=ARCH — prints HWR names (that's hardware register, the thing the rdhwr instruction uses) matched to whatever CPU or architecture you put in ARCH. No ARCH? Then it just picks HWR names based on the architecture and CPU of the binary you're disassembling. 🦋
• reg-names=ABI — prints GPR and FPR names to fit the selected ABI.
• reg-names=ARCH — prints CPU-specific register names (so, CP0 register and HWR names) to fit the selected CPU or architecture.

Okay so for any of the options listed above, you can pass ABI or ARCH as a number instead and it'll print numbers rather than names, for whichever register types you asked about. And you can list the available values of ABI and ARCH with the --help option. iykyk 💅

VAX girlies, this one's for you 👑 you can specify function entry addresses with -M entry:0xf00ba. Use it multiple times to properly disassemble VAX binary files that have no symbol tables (ROM dumps, we see you 🙈). Without this, the function entry mask gets decoded as VAX instructions and that would probably lead to the rest of the function being wrongly disassembled. Not the serve we wanted.

---

• -p, --private-headers — print information specific to the object file format. What exactly gets printed depends on the object file format you're dealing with, and for some object file formats literally no extra info is printed. It's giving mystery 💀
• -P options, --private=options — print information specific to the object file format. Here options is a comma separated list that depends on the format (and the lists of options get displayed with the help).

For XCOFF, the available options are:

• "header"
• "aout"
• "sections"
• "syms"
• "relocs"
• "lineno,"
• "loader"
• "except"
• "typchk"
• "traceback"
• "toc"
• "ldinfo"

For PE, the available options are:

• "header"
• "sections"

Not all object formats support this option. In particular the ELF format does not use it.

• -r, --reloc — print the relocation entries of the file. If you use it with -d or -D, the relocations get printed interspersed with the disassembly. Obsessed 🔥
• -R, --dynamic-reloc — print the dynamic relocation entries of the file. This is only meaningful for dynamic objects, like certain types of shared libraries. And just like -r, if used with -d or -D, the relocations are printed interspersed with the disassembly.

Note: objdump does not support displaying RELR type relocations. These can be displayed by the readelf program.

• -s, --full-contents — display the full contents of sections, often paired with -j when you want specific sections. By default all non-empty non-bss sections are displayed. By default any compressed section is displayed in its compressed form. To see the contents decompressed, add the -Z option to the command line. 🎀
• -S, --source — display source code intermixed with the disassembly, if possible. Implies -d.
• --show-all-symbols — when disassembling, show every symbol that matches a given address, not just the first one. Main character behaviour tbh.
• --source-comment[=txt] — like the -S option, but all source code lines get displayed with a prefix of txt. Usually txt is a comment string, which is how you tell the assembler code apart from the source code. If txt isn't provided then a default string of "# " (hash followed by a space) is used.
• --prefix=prefix — specify prefix to add to the absolute paths when used with -S.
• --prefix-strip=level — indicate how many initial directory names to strip off the hardwired absolute paths. It has no effect without --prefix=prefix, so don't bother doing it solo.
• --show-raw-insn — when disassembling instructions, print the instruction in hex as well as in symbolic form. This is the default except when --prefix-addresses is used.
• --no-show-raw-insn — when disassembling instructions, do not print the instruction bytes. This is the default when --prefix-addresses is used.
• --insn-width=width — display width bytes on a single line when disassembling instructions.
• --visualize-jumps[=color|=extended-color|=off] — visualize jumps that stay inside a function by drawing ASCII art between the start and target addresses 🦋. The optional =color argument adds color to the output using simple terminal colors. Alternatively the =extended-color argument will add color using 8bit colors, but those might not work on all terminals (rip).

If you need to disable the visualize-jumps option after it was previously enabled, then use visualize-jumps=off.

• --disassembler-color=off
• --disassembler-color=terminal
• --disassembler-color=on|color|colour
• --disassembler-color=extended|extended-color|extended-colour

These enable or disable colored syntax highlighting in disassembly output. The default behaviour is determined via a configure time option. Note that not all architectures support colored syntax highlighting, and depending on the terminal you're using, colored output may not actually be legible. 😭

• The on argument adds colors using simple terminal colors.
• The terminal argument does the same, but only if the output device is a terminal.
• The extended-color argument is similar to the on argument, but uses 8-bit colors. These may not work on all terminals.
• The off argument disables colored disassembly.

• -W[lLiaprmfFsoORtUuTgAckK]
• --dwarf[=rawline,=decodedline,=info,=abbrev,=pubnames,=aranges,=macro,=frames,=frames-interp,=str,=str-offsets,=loc,=Ranges,=pubtypes,=trace_info,=trace_abbrev,=trace_aranges,=gdb_index,=addr,=cu_index,=links,=follow-links]

Displays the contents of the DWARF debug sections in the file, if any are present. Compressed debug sections are automatically decompressed (temporarily) before they get displayed. If one or more of the optional letters or words follows the switch, then only those type(s) of data will be dumped. The letters and words refer to the following info:

• a, =abbrev — Displays the contents of the .debug_abbrev section.
• A, =addr — Displays the contents of the .debug_addr section.
• c, =cu_index — Displays the contents of the .debug_cu_index and/or .debug_tu_index sections.
• f, =frames — Display the raw contents of a .debug_frame section.
• F, =frames-interp — Display the interpreted contents of a .debug_frame section.
• g, =gdb_index — Displays the contents of the .gdb_index and/or .debug_names sections.
• i, =info — Displays the contents of the .debug_info section. Note: the output from this option can also be restricted by the use of the --dwarf-depth and --dwarf-start options.
• k, =links — Displays the contents of the .gnu_debuglink, .gnu_debugaltlink and .debug_sup sections, if any of them are present. Also displays any links to separate dwarf object files (dwo), if they are specified by the DW_AT_GNU_dwo_name or DW_AT_dwo_name attributes in the .debug_info section.
• K, =follow-links — Display the contents of any selected debug sections that are found in linked, separate debug info file(s). This can result in multiple versions of the same debug section being displayed if it exists in more than one file.

In addition, when displaying DWARF attributes, if a form is found that references the separate debug info file, then the referenced contents will also be displayed.

Note — in some distributions this option is enabled by default. It can be disabled via the N debug option. The default can be chosen when configuring the binutils via the --enable-follow-debug-links=yes or --enable-follow-debug-links=no options. If these are not used then the default is to enable the following of debug links.

Note — if support for the debuginfod protocol was enabled when the binutils were built, then this option will also include an attempt to contact any debuginfod servers mentioned in the DEBUGINFOD_URLS environment variable. This could take some time to resolve. This behaviour can be disabled via the =do-not-use-debuginfod debug option. ⏳

• N, =no-follow-links — Disables the following of links to separate debug info files.
• D, =use-debuginfod — Enables contacting debuginfod servers if there is a need to follow debug links. This is the default behaviour.
• E, =do-not-use-debuginfod — Disables contacting debuginfod servers when there is a need to follow debug links.
• l, =rawline — Displays the contents of the .debug_line section in a raw format.
• L, =decodedline — Displays the interpreted contents of the .debug_line section.
• m, =macro — Displays the contents of the .debug_macro and/or .debug_macinfo sections.
• o, =loc — Displays the contents of the .debug_loc and/or .debug_loclists sections.
• O, =str-offsets — Displays the contents of the .debug_str_offsets section.
• p, =pubnames — Displays the contents of the .debug_pubnames and/or .debug_gnu_pubnames sections.
• r, =aranges — Displays the contents of the .debug_aranges section.
• R, =Ranges — Displays the contents of the .debug_ranges and/or .debug_rnglists sections.
• s, =str — Displays the contents of the .debug_str, .debug_line_str and/or .debug_str_offsets sections.
• t, =pubtype — Displays the contents of the .debug_pubtypes and/or .debug_gnu_pubtypes sections.
• T, =trace_aranges — Displays the contents of the .trace_aranges section.
• u, =trace_abbrev — Displays the contents of the .trace_abbrev section.
• U, =trace_info — Displays the contents of the .trace_info section.

Note: displaying the contents of .debug_static_funcs, .debug_static_vars and debug_weaknames sections is not currently supported. 💀 yeah bestie, that one's just... not a thing yet. We move.

---

✨ OPTIONS ✨ (part 4, we're almost free)

• --dwarf-depth=n — caps how deep the dump of the .debug_info section goes: only n children, no further. This one's only useful when you're rolling with --debug-dump=info. Default behaviour is to print every DIE; and plot twist, the special value 0 for n gives you that same print-everything result too. With a non-zero n, any DIE sitting at or deeper than n levels just doesn't get printed. Heads up: the range for n is zero-based. 🫶
• --dwarf-start=n — prints only the DIEs beginning with the DIE numbered n. Again, only useful with --debug-dump=info. If you use it, it suppresses printing of any header info and all the DIEs before the one numbered n — you get only siblings and children of the DIE you picked. Team it up with --dwarf-depth if you want, it plays nice. 🌸
• --dwarf-check — turns on extra checks for consistency of Dwarf information. Vibe check for your debug info, lowkey.
• --debug-dir=dir — searches dir when it goes looking for separate debug info files.
• --ctf[=section] — displays the contents of the CTF section you name. CTF sections got a whole situation going on: they contain many subsections, and every single one gets displayed in order. By default it displays the section named .ctf, which is the name ld emits.
• --ctf-parent=member — okay so if a CTF section has ambiguously-defined types, it's actually an archive of many CTF dictionaries, and all of them inherit from one dictionary holding the unambiguous types. That member is by default named .ctf, same as the section containing it — but you can change that name at link time using the ctf_link_set_memb_name_changer function. So when you're staring at CTF archives built by a linker that used the name changer to rename the parent archive member, --ctf-parent lets you specify the name used for the parent. 👑
• --ctf-parent-section=section — this one lets you pick a completely different section for the CTF parent dictionary (the unambiguous-types one) than for the child dictionaries (the ambiguous remainder). The linker doesn't emit ELF objects structured like this, but some third-party linkers might. It's also just convenient for inspecting CTF written out as multiple raw files so you can compose them with objcopy — which can put them in different ELF sections but not in different members of a single CTF dict. iykyk. ✨
• --sframe[=section] — displays the contents of the SFrame section you name. By default, displays the name of the section named .sframe, which is the name emitted by ld.
• -G, --stabs — displays the full contents of any sections requested. It shows the contents of the .stab, .stab.index and .stab.excl sections from an ELF file. This is only useful on systems (think Solaris 2.0) where ".stab" debugging symbol-table entries live inside an ELF section. On most other file formats, debugging symbol-table entries are interleaved with linkage symbols and you'll see them in the --syms output instead. 🦋
• --start-address=address — starts displaying data at the address you give. This affects the output of the -d, -r and -s options.
• --stop-address=address — stops displaying data at the address you give. This also affects the output of the -d, -r and -s options.
• -t, --syms — prints the symbol table entries of the file. Similar to what nm gives you, though the display format is different. The format of the output depends on the format of the file being dumped, but there are two main types. One looks like this:

[  4](sec  3)(fl 0x00)(ty   0)(scl   3) (nx 1) 0x00000000 .bss
[  6](sec  1)(fl 0x00)(ty   0)(scl   2) (nx 0) 0x00000000 fred

where the number inside the square brackets is the number of the entry in the symbol table, the sec number is the section number, the fl value is the symbol's flag bits, the ty number is the symbol's type, the scl number is the symbol's storage class, and the nx value is the number of auxiliary entries associated with the symbol. The last two fields are the symbol's value and its name. 💅

The other common output format — usually seen with ELF-based files — looks like this:

00000000 l    d  .bss   00000000 .bss
00000000 g       .text  00000000 fred

Here the first number is the symbol's value (sometimes called its address). The next field is actually a set of characters and spaces showing which flag bits are set on the symbol — those characters are described below. Next up is the section the symbol is associated with, or *ABS* if the section is absolute (aka not connected with any section at all), or *UND* if the section is referenced in the file being dumped but not defined there.

After the section name comes another field — a number — which for common symbols is the alignment and for other symbols is the size. And finally, the symbol's name gets displayed. 🌈

The flag characters are divided into 7 groups, bestie, listen up:

• "l", "g", "u", "!" — the symbol is a local (l), global (g), unique global (u), neither global nor local (a space), or both global and local (!). A symbol can be neither local nor global for all sorts of reasons (debugging, for instance), but honestly it's probably a sign of a bug if it's ever both local and global. Unique global symbols are a GNU extension to the standard set of ELF symbol bindings — for such a symbol, the dynamic linker makes sure that across the entire process there's just one symbol with this name and type in use. ✨
• "w" — the symbol is weak (w) or strong (a space).
• "C" — the symbol denotes a constructor (C) or an ordinary symbol (a space).
• "W" — the symbol is a warning (W) or a normal symbol (a space). A warning symbol's name is a message to be displayed if the symbol following the warning symbol is ever referenced. 😭
• "I", "i" — the symbol is an indirect reference to another symbol (I), a function to be evaluated during reloc processing (i), or a normal symbol (a space).
• "d", "D" — the symbol is a debugging symbol (d), a dynamic symbol (D), or a normal symbol (a space).
• "F", "f", "O" — the symbol is the name of a function (F), a file (f), an object (O), or just a normal symbol (a space).
• -T, --dynamic-syms — prints the dynamic symbol table entries of the file. This is only meaningful for dynamic objects, like certain types of shared libraries. Similar to what nm gives you when you hit it with the -D (--dynamic) option.

The output format is similar to what --syms produces, except that an extra field gets inserted before the symbol's name, giving the version information associated with the symbol. If the version is the default version to be used when resolving unversioned references to the symbol, then it's displayed as is — otherwise it goes in parentheses. 🎀

• --special-syms — when displaying symbols, includes those the target considers special in some way, and which normally wouldn't be of interest to you.
• -U [d|i|l|e|x|h], --unicode=[default|invalid|locale|escape|hex|highlight] — controls the display of UTF-8 encoded multibyte characters in strings. The default (--unicode=default) gives them no special treatment at all. The --unicode=locale option displays the sequence in the current locale, which may or may not support them. The --unicode=hex and --unicode=invalid options display them as hex byte sequences enclosed by either angle brackets or curly braces.

The --unicode=escape option displays them as escape sequences (\uxxxx), and --unicode=highlight displays them as escape sequences highlighted in red (if your output device supports it). The colouring is meant to draw attention to unicode sequences showing up where they might not be expected. 👀

• -V, --version — prints the version number of objdump and exits. Bye bestie. 👋
• -x, --all-headers — displays all available header information, including the symbol table and relocation entries. Using -x is equivalent to specifying all of -a -f -h -p -r -t at once. The whole buffet, no cap. 🔥
• -w, --wide — formats some lines for output devices with more than 80 columns. Also stops truncating symbol names when they're displayed. Give your symbols room to breathe. 🌸
• -z, --disassemble-zeroes — normally the disassembly output skips blocks of zeroes. This option directs the disassembler to disassemble those blocks, just like any other data. Iconic zeroes deserve screen time too. 💅
• -Z, --decompress — the -Z option is meant to be used in conjunction with the -s option. It instructs objdump to decompress any compressed sections before displaying their contents.
• @file — reads command-line options from file. The options read get inserted in place of the original @file option. If file doesn't exist, or can't be read, then the option is treated literally and isn't removed.

Options in file are separated by whitespace. A whitespace character can be included inside an option by wrapping the whole option in either single or double quotes. Any character (yes, even a backslash) can be included by prefixing it with a backslash. The file can itself contain additional @file options — and any of those get processed recursively. 🌀

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🌈 SEE ALSO

nm(1), readelf(1), and the Info entries for binutils. Go read those too, bestie, they're the supporting cast and they ate. 🫶

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👑 COPYRIGHT

Copyright (c) 1991-2026 Free Software Foundation, Inc.

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, with no Front-Cover Texts, and with no Back-Cover Texts. A copy of the license is included in the section entitled "GNU Free Documentation License". 🎀

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And that's a wrap on objdump(1)! This one's pulled from the binutils-2.47 release, dated 2026-09-19. Go forth and disassemble, bestie — you got this. 💖✨🦋