otool − object file displaying tool


otool [ option ... ] [ file ... ]


The otool command displays specified parts of object files or libraries. If the, −m option is not used, the file arguments may be of the form libx.a(foo.o), to request information about only that object file and not the entire library. (Typically this argument must be quoted, ’’libx.a(foo.o)’’, to get it past the shell.) Otool understands both Mach-O (Mach object) files and fat file formats. Otool can display the specified information in either its raw (numeric) form (without the −v flag), or in a symbolic form using macro names of constants, etc. (with the −v or −V flag).

At least one of the following options must be specified:


Display the archive header, if the file is an archive.


Display the contents of the ’__.SYMDEF’ file, if the file is an archive.


Display the fat headers.


Display the Mach header.


Display the load commands.


Display the names and version numbers of the shared libraries that the object file uses.


Display just install name of a shared library.

−s segname sectname

Display the contents of the section (segname,sectname). If the −v flag is specified, the section is displayed as its type, unless the type is zero (the section header flags). Also the sections (__OBJC,__protocol), (__OBJC,__string_object) and (__OBJC,__runtime_setup) are displayed symbolically if the −v flag is specified.


Display the contents of the (__TEXT,__text) section. With the −v flag, this disassembles the text. And with −V, it also symbolically disassembles the operands.


Display the contents of the (__DATA,__data) section.


Display the contents of the __OBJC segment used by the Objective-C run-time system.


Display the relocation entries.


Display the argument strings (argv[] and envp[]) from a core file.


Display the indirect symbol table.


Display the table of contents for a dynamically linked shared library.


Display the reference table of a dynamically linked shared library.


Display the module table of a dynamically linked shared library.


Display the two-level namespace hints table.

The following options may also be given:

Used with the −t and −v or −V options to start the disassembly from symbol name and continue to the end of the (__TEXT,__text) section.


Display verbosely (symbolically) when possible.


Display the disassembled operands symbolically (this implies the −v option). This is useful with the −t option.


Don’t display leading addresses when displaying contents of sections.

−arch arch_type

Specifies the architecture, arch_type, of the file for otool(1) to operate on when the file is a fat file. (See arch(3) for the currently know arch_types.) The arch_type can be "all" to operate on all architectures in the file. The default is to display only the host architecture, if the file contains it; otherwise, all architectures in the file are shown.


The object file names are not assumed to be in the archive(member) syntax, which allows file names containing parenthesis.