OBJDUMP(1)

📦
version 2.35.1 · 2 versions
, in debian bookworm, ubuntu noble, ubuntu resolute

👑 OBJDUMP(1) — GNU Development Tools 👑

okay so bestie, this is the manual page for objdump, and it lives in the GNU Development Tools family. it's a big one, so we're doing this in parts. part 1, let's go 💅

✨ NAME ✨

objdump — it displays information from object files. that's the whole vibe. 🦋

🌸 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]
        [-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]]
        [--ctf=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]
        [--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]
        [-V|--version]
        [-H|--help]
        objfile...

💜 DESCRIPTION 💜

so objdump shows you info about one or more object files. the options are what decide which info you get. ngl this stuff is mostly for the programmers working on the compilation tools themselves — the compiler-girlies — not so much for the programmers who just want their program to compile and run. different audience, different energy ✨

objfile... are the object files you want examined. and when you hand it archives? it shows you info on each of the member object files inside. slay, no file left behind 🫶

🎀 OPTIONS 🎀

the long and short forms of options are shown here as alternatives, and they are equivalent — pick whichever, they're the same thing fr fr.

🚨 okay important: you have to 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. no options, no output, periodt.
  • -a, --archive-header — if any of the objfile files are archives, this shows the archive header info (in a format that's giving very much ls -l). and besides everything you could already list with ar tv, objdump -a also shows you the object file format of each archive member. extra, in the best way 💅
  • --adjust-vma=offset — when it's dumping info, it first adds offset to all the section addresses. super useful when your section addresses don't match up with the symbol table — which can happen when you're putting sections at particular addresses using a format that can't represent section addresses, like a.out. 😭
  • -b bfdname, --target=bfdname — tells it that the object-code format for your object files is bfdname. honestly you might not even need this; objdump can automatically recognize many formats. icon behavior.

for example:

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

displays summary information 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. and you can list all the formats available with the -i option 🌈

  • -C, --demangle[=style] — decodes (demangles) those low-level symbol names back into user-level names. besides stripping off any initial underscore the system prepended, this is what makes C++ function names actually readable. different compilers have different mangling styles, so the optional demangling style argument lets you pick the right one for your compiler 🎀
  • --recurse-limit, --no-recurse-limit, --recursion-limit, --no-recursion-limit — turns a limit on recursion on or off while demangling strings. here's the tea: name mangling formats allow for an infinite level of recursion, so it's totally possible to create strings whose decoding will eat up all the stack space on your host machine and trigger a memory fault 💀 the limit tries to stop that from happening by capping recursion at 2048 levels of nesting.

the default is for this limit to be enabled. but disabling it may be necessary if you need to demangle truly complicated names. that said — if the recursion limit is disabled, stack exhaustion is possible, and any bug reports about such an event will be rejected. so, like, choose wisely bestie 🙈

  • -g, --debugging — displays debugging information. it tries to parse the STABS debugging format info stored in the file and print it out using a C-like syntax. and if no STABS debugging was found, this option falls back on the -W option to print any DWARF info in the file. flexible queen 👑
  • -e, --debugging-tags — like -g, but the info comes out in a format that's compatible with the ctags tool. same energy, different outfit 💖
  • -d, --disassemble, --disassemble=symbol — displays the assembler mnemonics for the machine instructions from the input file. this option only disassembles those sections that are expected to contain instructions. if you give the optional symbol argument, it starts the mnemonics at symbol. if symbol is a function name, disassembly stops at the end of the function; otherwise it stops when the next symbol shows up. and if there are no matches for symbol? nothing gets displayed. ghosted 🫥

also note: if the --dwarf=follow-links option has also been enabled, then any symbol tables in linked debug info files will be read in and used when disassembling. ikyk ✨

  • -D, --disassemble-all — like -d, but it disassembles the contents of all sections, not just the ones expected to contain instructions.

this one also has a subtle effect on how instructions get disassembled in code sections. when -d is in effect, objdump assumes that any symbols present in a code section occur on the boundary between instructions, and it refuses to disassemble across such a boundary. when -D is in effect, that assumption is suppressed. so the output of -d and -D can genuinely differ — for example, if data is stored in code sections. 😳

if the target is an ARM architecture, this switch also forces the disassembler to decode pieces of data found in code sections as if they were instructions.

and note: if --dwarf=follow-links has also been enabled, any symbol tables in linked debug info files get read in and used when disassembling 🔥

  • --no-addresses — when disassembling, don't print addresses on each line, or for symbols and relocation offsets. paired with --no-show-raw-insn this may be useful for comparing compiler output 👀
  • --prefix-addresses — when disassembling, print the complete address on each line. this is the older disassembly format. vintage, lowkey 🦋
  • -EB, -EL, --endian={big|little} — specifies the endianness of the object files. this only affects disassembly. it can be useful when you're disassembling a file format that doesn't describe endianness info, like S-records 🌸
  • -f, --file-headers — displays summary info from the overall header of each of the objfile files 💫
  • -F, --file-offsets — when disassembling sections, whenever a symbol is displayed, this also displays the file offset of the region of data that's about to be dumped. if zeroes are being skipped, then when disassembly resumes it tells you how many zeroes were skipped and the file offset of the location from where the disassembly resumes. and when dumping sections, it displays the file offset of the location from where the dump starts. thorough 💅
  • --file-start-context — says that when displaying interlisted source code/disassembly (it assumes -S) from a file that hasn't been displayed yet, extend the context all the way to the start of the file 🎀
  • -h, --section-headers, --headers — displays summary info from the section headers of the object file.

file segments may get relocated to nonstandard addresses — for example by using the -Ttext, -Tdata, or -Tbss options to ld. but some object file formats, like a.out, do not store the starting address of the file segments. in those situations, even though 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. not me getting the wrong addresses 😭

also note, in some cases a section can have both the READONLY and the NOREAD attributes set. in those cases the NOREAD attribute takes precedence, but objdump will report both, since the exact setting of the flag bits might be important. receipts kept 📝

  • -H, --help — prints a summary of the options to objdump and exits. short, sweet, helpful 🫶
  • -i, --info — displays a list showing all architectures and object formats available for specification with -b or -m. the full menu, bestie 🍓
  • -j name, --section=name — displays information only for section name 🎯
  • -l, --line-numbers — labels the display (using debugging information) with the filename and source line numbers corresponding to the object code or relocs shown. only useful with -d, -D, or -r. context is everything ✨
  • -m machine, --architecture=machine — specifies the architecture to use when disassembling object files. handy when you're disassembling object files that don't describe architecture info, like S-records. you can list the available architectures with the -i option.

and if the target is an ARM architecture, this switch has an additional effect: it restricts disassembly to only those instructions supported by the architecture specified by machine. if you have to use this switch because the input file doesn't contain any architecture info, but you also want to disassemble all the instructions, use -marm 💅🔥

that's part 1 bestie, more is coming 👑

  • -M options, --disassembler-options=options — okay so this one is your lil' hotline to the disassembler itself 💬 you're passing target specific info straight through. Heads up tho: it's only supported on some targets. And if you need more than one of these bad boys? Either stack multiple -M options or just squish them into one comma separated list, both work, slay.

✨ ARC girlies ✨ here's your menu:

  • 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
  • fpud — selects the printing of FPU double precision FP instructions

Plus you can choose to have all the immediates printed in hexadecimal using hex. And like, by default? Short immediates get the decimal representation treatment, 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 is chillin' in the ELF file. This might be useful to select ARC EM or HS ISA, because the architecture is same for those and the disassembler relies on private ELF header data to decide if code is for EM or HS. You can specify this option multiple times — only the latest value will be used. Valid values are same as for the assembler -mcpu=... option, bestie.

If the target is an ARM architecture then this switch can be used to select which register name set is used during disassembler:

  • -M reg-names-std (the default) — selects 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'
  • -M reg-names-apcs — selects the name set used by the ARM Procedure Call Standard
  • -M reg-names-raw — just uses 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. Genuinely useful when you're attempting to disassemble thumb code produced by other compilers, no cap.

For AArch64 targets 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 disasssembly using -M notes. 🦋

For the x86, some of the 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.

For PowerPC, the -M argument raw selects disasssembly of hardware insns rather than aliases. For example, you will 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, e200z4, e300, e500, e500mc, e500mc64, e500x2, e5500, e6500, efs, power4, power5, power6, power7, power8, power9, power10, ppc, ppc32, ppc64, ppc64bridge, ppcps, pwr, pwr2, pwr4, pwr5, pwr5x, pwr6, pwr7, pwr8, pwr9, pwr10, pwrx, titan, and vle. 32 and 64 modify the default or a prior CPU selection, disabling and enabling 64-bit insns respectively. In addition, altivec, any, htm, vsx, and spe 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 files headers, but the result again may not be as you expect. 🙈

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.
  • "hwr-names=ARCH" — print HWR (hardware register, used by the "rdhwr" instruction) names as appropriate for the CPU or architecture specified by ARCH. By default, HWR names are selected according to the architecture and CPU of the binary being disassembled.
  • "reg-names=ABI" — print GPR and FPR names as appropriate for the selected ABI.
  • "reg-names=ARCH" — print CPU-specific register names (CP0 register and HWR names) as appropriate for the selected CPU or architecture.

For any of the options listed above, ABI or ARCH may be specified as numeric to have numbers printed rather than names, for the selected types of registers. You can list the available values of ABI and ARCH using the --help option. ✨

For VAX, you can specify function entry addresses with -M entry:0xf00ba. You can use this multiple times to properly disassemble VAX binary files that don't contain symbol tables (like ROM dumps). In these cases, the function entry mask would otherwise be decoded as VAX instructions, which would probably lead the rest of the function being wrongly disassembled. 😭

  • -p, --private-headers — prints information that is specific to the object file format. The exact information printed depends upon the object file format. And for some object file formats? no additional information is printed at all, rip.
  • -P options, --private=options — also prints information that is specific to the object file format. The argument options is a comma separated list that depends on the format (the lists of options is displayed with the help). 🫶

For XCOFF, the available options are:

  • "header"
  • "aout"
  • "sections"
  • "syms"
  • "relocs"
  • "lineno,"
  • "loader"
  • "except"
  • "typchk"
  • "traceback"
  • "toc"
  • "ldinfo"
Not all object formats support this option. In particular the ELF format does not use it. 💀
  • -r, --reloc — prints the relocation entries of the file. And if you use it with -d or -D, the relocations are printed interspersed with the disassembly. iconic.
  • -R, --dynamic-reloc — prints the dynamic relocation entries of the file. This is only meaningful for dynamic objects, such as certain types of shared libraries. As for -r, if used with -d or -D, the relocations are printed interspersed with the disassembly. 🔥
  • -s, --full-contents — displays the full contents of any sections requested. By default all non-empty sections are displayed.
  • -S, --source — displays source code intermixed with disassembly, if possible. Implies -d. 💖
  • --source-comment[=txt] — like the -S option, but all source code lines are displayed with a prefix of txt. Typically txt will be a comment string which can be used to distinguish the assembler code from the source code. If txt is not provided then a default string of "# " (hash followed by a space), will be used.
  • --prefix=prefix — specify prefix to add to the absolute paths when used with -S.
  • --prefix-strip=level — indicates how many initial directory names to strip off the hardwired absolute paths. It has no effect without --prefix=prefix. like, none, zero, nada.
  • --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] — okay so this one literally draws lil ASCII art arrows between the start address and the target address of jumps that stay inside one function 🎨 so you can see the flow. The optional =color arg makes it cute with basic terminal colors. Or =extended-color for the fancy 8-bit color palette — but ngl those might not render on every terminal, so vibe check first 💅

If you turned it on earlier and now you need it OFF, hit it with visualize-jumps=off. That's the off switch, no cap.

  • -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] — this dumps the DWARF debug sections if the file has any. Compressed debug sections get auto-decompressed (temporarily, bestie, just for the showing) before they hit your screen. If you tack on one or more of those optional letters/words after the switch, only those types of data get dumped ✨

The letters and words map to this info:

  • a, =abbrev — shows you the contents of the .debug_abbrev section.
  • A, =addr — shows you the contents of the .debug_addr section.
  • c, =cu_index — shows you the contents of the .debug_cu_index and/or .debug_tu_index sections.
  • f, =frames — dumps the raw contents of a .debug_frame section.
  • F, =frame-interp — dumps the interpreted contents of a .debug_frame section.
  • g, =gdb_index — shows you the contents of the .gdb_index and/or .debug_names sections.
  • i, =info — shows you the contents of the .debug_info section. Heads up 📌 the output from this one can also be reined in with the --dwarf-depth and --dwarf-start options.
  • k, =links — shows you the contents of the .gnu_debuglink and/or .gnu_debugaltlink sections. It also shows any links to separate dwarf object files (dwo), if they're specified by the DW_AT_GNU_dwo_name or DW_AT_dwo_name attributes in the .debug_info section.
  • K, =follow-links — shows the contents of any selected debug sections found in linked, separate debug info file(s). Word of warning ⚠️ this can result in multiple versions of the same debug section being displayed, if that section exists in more than one file. Also, when displaying DWARF attributes, if a form is found that references the separate debug info file, then the referenced contents get displayed too.
  • l, =rawline — shows you the contents of the .debug_line section in a raw format.
  • L, =decodedline — shows you the interpreted contents of the .debug_line section.
  • m, =macro — shows you the contents of the .debug_macro and/or .debug_macinfo sections.
  • o, =loc — shows you the contents of the .debug_loc and/or .debug_loclists sections.
  • O, =str-offsets — shows you the contents of the .debug_str_offsets section.
  • p, =pubnames — shows you the contents of the .debug_pubnames and/or .debug_gnu_pubnames sections.
  • r, =aranges — shows you the contents of the .debug_aranges section.
  • R, =Ranges — shows you the contents of the .debug_ranges and/or .debug_rnglists sections.
  • s, =str — shows you the contents of the .debug_str, .debug_line_str and/or .debug_str_offsets sections.
  • t, =pubtype — shows you the contents of the .debug_pubtypes and/or .debug_gnu_pubtypes sections.
  • T, =trace_aranges — shows you the contents of the .trace_aranges section.
  • u, =trace_abbrev — shows you the contents of the .trace_abbrev section.
  • U, =trace_info — shows you 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. Sad but true 😔
  • --dwarf-depth=n — caps the dump of the ".debug_info" section at n children. Only useful with --debug-dump=info. By default it prints all the DIEs, and the special value 0 for n does the same thing (so yes, 0 = all of them, iconic behavior 💅). With a non-zero value for n, DIEs at or deeper than n levels will not be printed. And the range for n is zero-based, so keep that in mind.
  • --dwarf-start=n — prints only DIEs beginning with the DIE numbered n. Only useful with --debug-dump=info. If you specify it, this option suppresses printing of any header information and all DIEs before the DIE numbered n. Only siblings and children of the specified DIE get printed. You can totally use this one together with --dwarf-depth 🫶
  • --dwarf-check — turns on extra checks for consistency of Dwarf information. Basically a vibe check for your debug data ✨
  • --ctf=section — displays the contents of the specified CTF section. CTF sections themselves contain a bunch of subsections, and all of them get displayed in order.
  • --ctf-parent=section — specifies the name of another section from which the CTF dictionary can inherit types. (If you don't specify one, we assume the CTF dictionary inherits types from the default-named member of the archive contained within this section.)
  • -G, --stabs — displays the full contents of any sections requested. Displays the contents of the .stab, .stab.index and .stab.excl sections from an ELF file. This is only useful on systems (such as Solaris 2.0) where ".stab" debugging symbol-table entries are carried in an ELF section. In most other file formats, debugging symbol-table entries are interleaved with linkage symbols, and are visible in the --syms output. Iykyk 🧚
  • --start-address=address — starts displaying data at the specified address. This affects the output of the -d, -r and -s options.
  • --stop-address=address — stops displaying data at the specified address. This affects the output of the -d, -r and -s options.
  • -t, --syms — prints the symbol table entries of the file. This is similar to the info the nm program gives you, except 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 are 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 referred to as its address). The next field is actually a set of characters and spaces indicating the flag bits that are set on the symbol. These characters are described below. Next is the section with which the symbol is associated, or *ABS* if the section is absolute (ie not connected with any section), 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 symbol is the size. Finally the symbol's name is displayed.

The flag characters are divided into 7 groups, bestie, buckle 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 or global for a variety of reasons, e.g., because it is used for debugging, but it is probably an indication of a bug if it is 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 will make sure that in the entire process there is just one symbol with this name and type in use. One of one 💅
  • 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) or a dynamic symbol (D) or a normal symbol (a space).
  • F, f, O — the symbol is the name of a function (F) or a file (f) or 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. It's similar to the info the nm program gives you when you pass it the -D (--dynamic) option.

The output format is similar to what --syms produces, except an extra field gets inserted before the symbol's name, giving the version info 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 gets put into parentheses.

  • --special-syms — when displaying symbols, includes the ones the target considers to be special in some way, and which would not normally be of interest to the user. Sneaky lil extras 🙈
  • -V, --version — prints the version number of objdump and dips ✌️
  • -x, --all-headers — bestie this is the give me everything option 💖 It shows every single bit of header info available, and yes that includes the symbol table and the relocation entries too. Using -x is literally the same as spelling out all of -a -f -h -p -r -t. One flag, whole buffet. Iconic. ✨
  • -w, --wide — for when your terminal is being a main character and has more than 80 columns 👑 This formats some lines to actually use all that space. Also? It stops truncating symbol names when they get displayed. No more very_long_symbol_na... heartbreak. 💅
  • -z, --disassemble-zeroes — okay so normally the disassembly output just skips right over blocks of zeroes like they're not even there 🙈 This option tells the disassembler no bestie, we're looking at those too, and it disassembles them just like any other data. No cap.
  • @file — read command-line options straight out of file. The options it reads get inserted in place of the original @file option, like they were always there. And if file doesn't exist, or can't be read? Then the option is just treated literally and not removed. It stays. It's giving "we tried". 😭

Options inside file are separated by whitespace. Wanna sneak a whitespace character into an option? Wrap the whole option in either single or double quotes 🎀 And any character — yes, even a backslash — can be included by prefixing it with a backslash. Also wild: the file may itself contain more @file options, and any of those get processed recursively. It's @files all the way down, fr fr. 🌀

🌈 SEE ALSO 🌈

nm(1), readelf(1), and the Info entries for binutils.

Go read those too, they're the friend group. 🫶

Copyright (c) 1991-2020 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".

That's the legal bit, bestie — don't skip it, it's load-bearing. 🎀

And that's the whole page, periodt. 💖 This beauty is from binutils-2.35.1, dated 2022-11-21, and it lives at the top of OBJDUMP(1). Go disassemble something and slay. 👑✨

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