scanmacho man page

scanmacho — user-space utility to scan Mach-O files


scanmacho [options] Mach-Os or directories


scanmacho 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

Mach-O Filetypes

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)

Mach-O Bits

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


Reporting Bugs

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 if possible.

See Also

chpax(1), dumpelf(1), paxctl(1), pspax(1), readelf(1), scanelf(1), elf(5)


Ned Ludd <>


Mike Frysinger <>


Fabian Groffen <>

Mach-O Maintainer




11/12/2016 pax-utils 1.1.7 Documentation for pax-utils