scanmacho(1) user-space utility to scan Mach-O files


scanmacho [options] Mach-Os or directories



is a user-space utility to quickly scan given Mach-Os, directories, or common system paths for different information. This may include Mach-O types, their install_names, etc...

Because Mach-O files can be "fat", it is possible for a single file to return multiple lines. Each line represents a single architecture, contained in the fat (universal) file. While there are no real restrictions, in practice, the entries can be distinguished by their arch type, e.g. ppc, ppc64, i386, x86_64, arm, ...


-A, --archives

Scan archives (.a files)

-a, --all

Print all useful/simple info

-B, --nobanner

Don't display the header

-b, --bind

Print flags from mach_header

-D, --endian

Print Mach-O endianness

-E, --etype filetype

Print only Mach-O files matching specified etype (like MH_EXECUTABLE, MH_DYLIB, etc...)

-F, --format FORMAT

Use specified format for output; see the FORMAT section for more information.

-f, --from FILE

Read input stream from specified filename

-g, --gmatch

Use strncmp to match libraries (use with -N). Or regexp with symbol matching

-h, --help

Show condensed usage and exit

-i, --interp

Print the interpreter information (LC_LOAD_DYLINKER)

-M, --bits BITS

Print only Mach-O files matching specified numeric bits (like 32/64)

-m, --mount

Don't recursively cross mount points


Find Mach-Os that need the specified INSTALL_NAME

-n, --needed

Print libraries the Mach-O is linked against (LC_LOAD_DYLIB).

-O, --perms PERMS

Print only Mach-O files with matching specified octal bits (like 755).

-o, --file FILE

Write output stream to specified filename.

-p, --path

Scan all directories in PATH environment.

-q, --quiet

Only output 'bad' things.

-R, --recursive

Scan directories recursively

-r, --rpath

Print RPATH encoded in the Mach-O (LC_RPATH)

-S, --soname

Print the Mach-O's shared library name (install_name).

-V, --version

Print version and exit

-v, --verbose

Be verbose (can be used more than once)

-y, --symlink

Don't scan symlinks

-Z, --size SIZE

Print Mach-O file size


The format string is much like a printf string in that it is a literal string with flags requesting different information. For example, you could use a format string and expect the following results.

  # scanmacho -BF "file %f needs %n; funky time" /bin/bash
  file bash needs /usr/lib/libncurses.5.4.dylib,/usr/lib/libSystem.B.dylib; funky time

Note that when you use a format string, generally information related flags should be omitted. In other words, you do not want to try and request NEEDED output (-n) and try to specify a format output at the same time as these operations are mutually exclusive. Each information related flag has an equivalent conversion specifier, so use those instead. You can of course continue to use non-information related flags (such as --verbose).

There are three characters that introduce conversion specifiers.

% - replace with info

  • # - silent boolean match

  • + - verbose match

And there are a number of conversion specifiers. We try to match up the specifier with corresponding option.

a - arch type

  • b - mach_header flags

  • D - endian

  • F - long filename

  • f - short filename

  • i - dyld

  • M - CPU_TYPE class

  • N - specified needed

  • n - needed libraries

  • p - filename (minus search)

  • o - mh_type

  • O - perms

  • r - rpaths

  • S - install_name


You can narrow your search by specifying the Mach-O object file type. The commandline option takes the symbolic type name. Multiple values can be passed comma separated. Example -E MH_EXECUTE,MH_DYLIB

Here is the normal list available for your pleasure.

MH_OBJECT - intermediate object file (.o)

  • MH_EXECUTE - standard executable program

  • MH_BUNDLE - dlopen plugin (.bundle)

  • MH_DYLIB - dynamic shared library (.dylib)

  • MH_PRELOAD - executable not loaded by Mac OS X kernel (ROM)

  • MH_CORE - program crash core file

  • MH_DYLINKER - dynamic linker shared library (dyld)

  • MH_DYLIB_STUB - shared library stub for static only, no sections

  • MH_DSYM - debug symbols file (in .dSYM dir)


You can also narrow your search by specifying the Mach-O bitsize. Specify the numeric value.

32 - 32bit mach_header

  • 64 - 64bit mach_header_64


Please include as much information as possible (using any available debugging options) and send bug reports to the maintainers (see the AUTHORS section). Please use the Gentoo bugzilla at m[blue][] if possible.


Ned Ludd <[email protected]>


Mike Frysinger <[email protected]>


Fabian Groffen <[email protected]>

Mach-O Maintainer