READELF(1)

📦
version 26.09 · 2 versions
, in nixpkgs unstable

🦋 readelf(1) — GNU Development Tools 🦋

✨ NAME ✨

readelf — display information about ELF files

🌸 SYNOPSIS 🌸

readelf [-a|--all]
        [-h|--file-header]
        [-l|--program-headers|--segments]
        [-S|--section-headers|--sections]
        [-g|--section-groups]
        [-t|--section-details]
        [-e|--headers]
        [-s|--syms|--symbols]
        [--dyn-syms|--lto-syms]
        [--sym-base=[0|8|10|16]]
        [--demangle=style|--no-demangle]
        [--quiet]
        [--recurse-limit|--no-recurse-limit]
        [-U method|--unicode=method]
        [-X|--extra-sym-info|--no-extra-sym-info]
        [-n|--notes]
        [-r|--relocs]
        [-u|--unwind]
        [-d|--dynamic]
        [-V|--version-info]
        [-A|--arch-specific]
        [-D|--use-dynamic]
        [-L|--lint|--enable-checks]
        [-x <number or name>|--hex-dump=<number or name>]
        [-p <number or name>|--string-dump=<number or name>]
        [-R <number or name>|--relocated-dump=<number or name>]
        [-j <number or name>|--display-section=<number or name>]
        [-z|--decompress]
        [-c|--archive-index]
        [-w[lLiaprmfFsoORtUuTgAck]|
         --debug-dump[=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]]
        [-wK|--debug-dump=follow-links]
        [-wN|--debug-dump=no-follow-links]
        [-wD|--debug-dump=use-debuginfod]
        [-wE|--debug-dump=do-not-use-debuginfod]
        [-P|--process-links]
        [--dwarf-depth=n]
        [--dwarf-start=n]
        [--ctf=section]
        [--ctf-parent=section]
        [--ctf-symbols=section]
        [--ctf-strings=section]
        [--sframe=section]
        [-I|--histogram]
        [--got-contents]
        [-v|--version]
        [-W|--wide]
        [-T|--silent-truncation]
        [-H|--help]
        elffile...

💅 DESCRIPTION 💅

okay so readelf is literally the bestie who displays information about one or more ELF format object files. The options are the vibe check that controls what particular information gets displayed. 😌

elffile... are the object files to be examined. 32-bit and 64-bit ELF files are supported, as are archives containing ELF files. 🫶

This program performs a similar function to objdump but it goes into more detail and it exists independently of the BFD library, so if there is a bug in BFD then readelf will not be affected. no cap, that independence is iconic ✨

🎀 OPTIONS 🎀

The long and short forms of options, shown here as alternatives, are equivalent. At least one option besides -v or -H must be given. fr fr.

  • -a, --all — Equivalent to specifying --file-header, --program-headers, --sections, --symbols, --relocs, --dynamic, --notes, --got-contents, --version-info, --arch-specific, --unwind, --section-groups and --histogram.
Note — this option does not enable --use-dynamic itself, so if that option is not present on the command line then dynamic symbols and dynamic relocs will not be displayed.
  • -h, --file-header — Displays the information contained in the ELF header at the start of the file.
  • -l, --program-headers, --segments — Displays the information contained in the file's segment headers, if it has any.
  • --quiet — Suppress "no symbols" diagnostic.
  • -S, --sections, --section-headers — Displays the information contained in the file's section headers, if it has any.
  • -g, --section-groups — Displays the information contained in the file's section groups, if it has any.
  • -t, --section-details — Displays the detailed section information. Implies -S.
  • -s, --symbols, --syms — Displays the entries in symbol table section of the file, if it has one. If a symbol has version information associated with it then this is displayed as well. The version string is displayed as a suffix to the symbol name, preceded by an @ character. For example foo@VER_1. If the version is the default version to be used when resolving unversioned references to the symbol then it is displayed as a suffix preceded by two @ characters. For example foo@@VER_2.
  • --dyn-syms — Displays the entries in dynamic symbol table section of the file, if it has one. The output format is the same as the format used by the --syms option.
  • --lto-syms — Displays the contents of any LTO symbol tables in the file.
  • --sym-base=[0|8|10|16] — Forces the size field of the symbol table to use the given base. Any unrecognized options will be treated as 0. --sym-base=0 represents the default and legacy behaviour. This will output sizes as decimal for numbers less than 100000. For sizes 100000 and greater hexadecimal notation will be used with a 0x prefix. --sym-base=8 will give the symbol sizes in octal. --sym-base=10 will always give the symbol sizes in decimal. --sym-base=16 will always give the symbol sizes in hexadecimal with a 0x prefix.
  • -C, --demangle[=style] — Decode (demangle) low-level symbol names into user-level names. This makes C++ function names readable. Different compilers have different mangling styles. The optional demangling style argument can be used to choose an appropriate demangling style for your compiler.
  • --no-demangle — Do not demangle low-level symbol names. This is the default.
  • --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 is possible to create strings whose decoding will exhaust the amount of stack space available on the host machine, triggering a memory fault. The limit tries to prevent this from happening 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.

Careful, bestie: if the recursion limit is disabled then stack exhaustion is possible and any bug reports about such an event will be rejected. 💀
  • -U [d|i|l|e|x|h], --unicode=[default|invalid|locale|escape|hex|highlight] — Controls the display of non-ASCII characters in identifier names. The default (--unicode=locale or --unicode=default) is to treat them as multibyte characters and display them in the current locale. All other versions of this option treat the bytes as UTF-8 encoded values and attempt to interpret them. If they cannot be interpreted or if the --unicode=invalid option is used then they are displayed as a sequence of hex bytes, enclosed in curly parenthesis characters.

Using the --unicode=escape option will display the characters as unicode escape sequences (\uxxxx). Using the --unicode=hex will display the characters as hex byte sequences enclosed between angle brackets.

Using the --unicode=highlight will display the characters as unicode escape sequences but it will also highlight them in red, assuming that colouring is supported by the output device. The colouring is intended to draw attention to the presence of unicode sequences when they might not be expected.

  • -X, --extra-sym-info — When displaying details of symbols, include extra information not normally presented. Currently this just adds the name of the section referenced by the symbol's index field, if there is one. In the future more information may be displayed when this option is enabled.

Enabling this option effectively enables the --wide option as well, at least when displaying symbol information.

  • --no-extra-sym-info — Disables the effect of the --extra-sym-info option. This is the default.
  • -e, --headers — Display all the headers in the file. Equivalent to -h -l -S.
  • -n, --notes — Displays the contents of the NOTE segments and/or sections, if any.
  • -r, --relocs — Displays the contents of the file's relocation section, if it has one.
  • -u, --unwind — Displays the contents of the file's unwind section, if it has one. Only the unwind sections for IA64 ELF files, as well as ARM unwind tables (".ARM.exidx" / ".ARM.extab") are currently supported. If support is not yet implemented for your architecture you could try dumping the contents of the .eh_frames section using the --debug-dump=frames or --debug-dump=frames-interp options.
  • -d, --dynamic — Displays the contents of the file's dynamic section, if it has one.
  • -V, --version-info — Displays the contents of the version sections in the file, if they exist.
  • -A, --arch-specific — Displays architecture-specific information in the file, if there is any.
  • -D, --use-dynamic — When displaying symbols, this option makes readelf use the symbol hash tables in the file's dynamic section, rather than the symbol table sections.

When displaying relocations, this option makes readelf display the dynamic relocations rather than the static relocations.

  • -L, --lint, --enable-checks — Displays warning messages about possible problems with the file(s) being examined. If used on its own then all of the contents of the file(s) will be examined. If used with one of the dumping options then the warning messages will only be produced for the things being displayed.
  • -x <number or name>, --hex-dump=<number or name> — Displays the contents of the indicated section as hexadecimal bytes. A number identifies a particular section by index in the section table; any other string identifies all sections with that name in the object file. This option can be repeated multiple times on the command line in order to request multiple hex dumps.
  • -R <number or name>, --relocated-dump=<number or name> — Displays the contents of the indicated section as hexadecimal bytes. A number identifies a particular section by index in the section table; any other string identifies all sections with that name in the object file. The contents of the section will be relocated before they are displayed. This option can be repeated multiple times on the command line in order to request multiple relocated dumps.
  • -p <number or name>, --string-dump=<number or name> — prints out the contents of whatever section you point at, as printable strings ✨. A number grabs one specific section by its index in the section table; any other string grabs all the sections with that name in the object file. And yes bestie, you can repeat this option on the command line as many times as you want to ask for multiple string dumps 💅
  • -j <number or name>, --display-section — dumps the contents of the section you name, formatted according to its section header type 🎀. Sections holding relocations get displayed like you'd passed --relocations, sections holding symbols get displayed like you'd passed --syms, and so on down the line.

A number identifies one particular section by its index in the section table; any other string means all sections with that name in the input file(s) 🦋.

Repeatable, literally as many times as you need, for multiple section dumps.

  • -z, --decompress — asks readelf to decompress the section(s) being dumped by the x, R or p options before showing them to you 🌸. If the section(s) aren't compressed, they just get displayed as-is, no drama.
  • -c, --archive-index — shows the file symbol index info living in the header part of binary archives 📚. Does exactly the same job as the t command to ar, except it doesn't touch the BFD library. Iconic lowkey.
  • -w[lLiaprmfFsOoRtUuTgAckK], --debug-dump[=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] — dumps the contents of the DWARF debug sections in the file, if there are any 💖. Compressed debug sections get automatically decompressed (temporarily!) before display. If you follow the switch with one or more of the optional letters or words, only those type(s) of data get dumped. Letters and words map like this:
    • a / =abbrev — dumps the contents of the .debug_abbrev section.
    • A / =addr — dumps the contents of the .debug_addr section.
    • c / =cu_index — dumps the contents of the .debug_cu_index and/or .debug_tu_index sections.
    • f / =frames — shows the raw contents of a .debug_frame section.
    • F / =frames-interp — shows the interpreted contents of a .debug_frame section.
    • g / =gdb_index — dumps the contents of the .gdb_index and/or .debug_names sections.
    • i / =info — dumps the contents of the .debug_info section. Heads up 🫶: the output from this one can also be restricted using the --dwarf-depth and --dwarf-start options.
    • k / =links — dumps the contents of the .gnu_debuglink, .gnu_debugaltlink and .debug_sup sections, if any of them are there. Also displays 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 — displays the contents of any selected debug sections found in linked, separate debug info file(s) 🧚. Ngl this can mean multiple versions of the same debug section get displayed, if it exists in more than one file.

Also, when displaying DWARF attributes, if a form shows up that references the separate debug info file, the referenced contents get displayed too.

Note — on some distributions this option is enabled by default. You can turn it off via the N debug option. The default can be picked when configuring binutils with the --enable-follow-debug-links=yes or --enable-follow-debug-links=no options. If neither is used, the default is to enable the following of debug links 💫
Note — if support for the debuginfod protocol was enabled when binutils was built, then this option will also include an attempt to contact any debuginfod servers mentioned in the DEBUGINFOD_URLS environment variable 😭. That could take a while to resolve. Disable it via the =do-not-use-debuginfod debug option.
  • N / =no-follow-links — disables following links to separate debug info files 💀.
  • D / =use-debuginfod — enables contacting debuginfod servers when there's a need to follow debug links. This is the default behaviour ⭐.
  • E / =do-not-use-debuginfod — disables contacting debuginfod servers when there's a need to follow debug links.
  • l / =rawline — dumps the contents of the .debug_line section in a raw format.
  • L / =decodedline — dumps the interpreted contents of the .debug_line section.
  • m / =macro — dumps the contents of the .debug_macro and/or .debug_macinfo sections.
  • o / =loc — dumps the contents of the .debug_loc and/or .debug_loclists sections.
  • O / =str-offsets — dumps the contents of the .debug_str_offsets section.
  • p / =pubnames — dumps the contents of the .debug_pubnames and/or .debug_gnu_pubnames sections.
  • r / =aranges — dumps the contents of the .debug_aranges section.
  • R / =Ranges — dumps the contents of the .debug_ranges and/or .debug_rnglists sections.
  • s / =str — dumps the contents of the .debug_str, .debug_line_str and/or .debug_str_offsets sections.
  • t / =pubtype — dumps the contents of the .debug_pubtypes and/or .debug_gnu_pubtypes sections.
  • T / =trace_aranges — dumps the contents of the .trace_aranges section.
  • u / =trace_abbrev — dumps the contents of the .trace_abbrev section.
  • U / =trace_info — dumps 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.
  • --dwarf-depth=n — limits the dump of the .debug_info section to n children 🌈. Only useful with --debug-dump=info. Default is to print all DIEs, and the special value 0 for n gives you that same effect. With a non-zero n, DIEs at or deeper than n levels don't get printed. The range for n is zero-based, iykyk.
  • --dwarf-start=n — prints only DIEs beginning with the DIE numbered n 🌟. Only useful with --debug-dump=info. If you specify it, it suppresses printing of any header info and all DIEs before the DIE numbered n — only siblings and children of the specified DIE get printed. Pairs beautifully with --dwarf-depth 💅.
  • -P, --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 get displayed.
  • --ctf[=section] — displays the contents of the specified CTF section 👑. CTF sections themselves contain lots of subsections, all of which get displayed in order. By default it displays the name of the section named .ctf, which is the name emitted by ld.
  • --ctf-parent=member — if the CTF section contains ambiguously-defined types, it'll consist of an archive of many CTF dictionaries, all inheriting from one dictionary that holds the unambiguous types 🎀. That member is by default named .ctf, same as the section containing it, but you can change the name using the ctf_link_set_memb_name_changer function at link time. So when you're looking at CTF archives made 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 one with unambiguous types) than the child dictionaries (the ones with the ambiguous remainder) 🦋. The linker doesn't emit ELF objects structured like that, but some third-party linkers might. It's also handy 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.
  • --ctf-symbols=section, --ctf-strings=section — specify the name of another section that the CTF file can inherit strings and symbols from 🌸. By default, the .symtab and its linked string table are used. And listen: if either --ctf-symbols or --ctf-strings is specified, the other must be specified too 👀.
  • --got-contents — displays the contents of the file's Global Offset Table (GOT) sections, if it has any 💖. For MIPS this option is similar to --arch-specific, but it only displays the GOT-related contents, and it gets ignored when --arch-specific is used.
  • -I, --histogram — displays a histogram of bucket list lengths when showing the contents of the symbol tables 📊.
  • -v, --version — displays the version number of readelf ✨.
  • -W, --wide — don't break output lines to fit into 80 columns 🫶. By default readelf breaks section header and segment listing lines for 64-bit ELF files so they fit into 80 columns. This option makes readelf print each section header — respectively each segment — on a single line, which is far more readable on terminals wider than 80 columns.
  • -T, --silent-truncation — normally, when readelf is displaying a symbol name and has to truncate it to fit into an 80 column display, it adds a suffix of "[...]" to the name 💅. This command line option disables that behaviour, letting 5 more characters of the name be displayed and restoring the old behaviour of readelf (prior to release 2.35).
  • -H, --help — displays the command-line options that readelf understands 🎀.
  • @file — ok so this is the little recursive queen of the option list 🫶 it reads your command-line options out of file instead, and the options it finds get inserted right where the @file was originally sitting, like a lil sleight of hand ✨

Lowkey important deets, bestie, don't skip:

  • If file doesn't exist, or it just refuses to be read (rude 💀), then the option gets treated literally — like, as plain text @file — and it is not removed from the command line. No cap.
  • Inside file, options are separated by whitespace. That's the vibe check. 🧚
  • Wanna sneak a whitespace character into an option? Wrap the whole option in single or double quotes and you're slaying 💅
  • Any character — and yes, that includes a backslash — can be included by prefixing it with a backslash. Escaping is that girl. 🦋
  • And the plot twist: file itself may contain additional @file options, and any of those get processed recursively. It's giving inception, it's giving mirror-in-a-mirror, it's iconic. 🪞👑
Ngl this is powerful and also exactly how you end up in an infinite @file loop. Just saying. Be normal about it. 😭

🎀 SEE ALSO 🎀

  • objdump(1) — go give her a visit, she's the other binutils bestie 💖
  • and the Info entries for binutils. Yes, the Info pages. They're giving vintage but they ate. 👑

Okay legal moment, everyone quiet down 🌸

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, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled "GNU Free Documentation License". 💜

And that's a wrap, bestie!! 🫶 This whole glow-up is from binutils-2.46.1, and the date stamp on it is the absolutely iconic 1980-01-01 — yes, the same date every single one of these pages claims, it's a whole running joke at this point 😭💀 go read your ELF files, you're doing amazing, mwah 🍓✨

📦 where this page comes from