LDD(1) BSD General Commands Manual LDD(1)NAME
ldd -- list dynamic object dependencies
SYNOPSIS
ldd [-a] [-v] [-f format] program ...
DESCRIPTION
The ldd utility displays all shared objects that are needed to run the given program or to load the given shared object. Contrary to nm(1),
the list includes ``indirect'' dependencies that are the result of needed shared objects which themselves depend on yet other shared objects.
Zero, one or two -f options may be given. The argument is a format string passed to rtld(1) and allows customization of ldd's output. If
one is given, it sets LD_TRACE_LOADED_OBJECTS_FMT1. If two are given, they set LD_TRACE_LOADED_OBJECTS_FMT1 and
LD_TRACE_LOADED_OBJECTS_FMT2, respectively. See rtld(1) for details, including a list of recognized conversion characters.
The -a option displays the list of all objects that are needed by each loaded object. This option does not work with a.out(5) binaries.
The -v option displays a verbose listing of the dynamic linking headers encoded in the executable. See the source code and include files for
the definitive meaning of all the fields.
EXAMPLES
The following is an example of a shell pipeline which uses the -f option. It will print a report of all ELF binaries in the current direc-
tory, which link against libc.so.6:
find . -type f | xargs -n1 file -F ' ' | grep ELF | cut -f1 -d' ' | xargs ldd -f '%A %o
' | grep libc.so.6
SEE ALSO ld(1), nm(1), rtld(1)HISTORY
A ldd utility first appeared in SunOS 4.0, it appeared in its current form in FreeBSD 1.1.
The -v support is based on code written by John Polstra <jdp@polstra.com>
BSD May 15, 2008 BSD
Check Out this Related Man Page
LDD(1) Linux Programmer's Manual LDD(1)NAME
ldd - print shared object dependencies
SYNOPSIS
ldd [option]... file...
DESCRIPTION
ldd prints the shared objects (shared libraries) required by each program or shared object specified on the command line. An example of
its use and output is the following:
$ ldd /bin/ls
linux-vdso.so.1 (0x00007ffcc3563000)
libselinux.so.1 => /lib64/libselinux.so.1 (0x00007f87e5459000)
libcap.so.2 => /lib64/libcap.so.2 (0x00007f87e5254000)
libc.so.6 => /lib64/libc.so.6 (0x00007f87e4e92000)
libpcre.so.1 => /lib64/libpcre.so.1 (0x00007f87e4c22000)
libdl.so.2 => /lib64/libdl.so.2 (0x00007f87e4a1e000)
/lib64/ld-linux-x86-64.so.2 (0x00005574bf12e000)
libattr.so.1 => /lib64/libattr.so.1 (0x00007f87e4817000)
libpthread.so.0 => /lib64/libpthread.so.0 (0x00007f87e45fa000)
In the usual case, ldd invokes the standard dynamic linker (see ld.so(8)) with the LD_TRACE_LOADED_OBJECTS environment variable set to 1.
This causes the dynamic linker to inspect the program's dynamic dependencies, and find (according to the rules described in ld.so(8)) and
load the objects that satisfy those dependencies. For each dependency, ldd displays the location of the matching object and the (hexadeci-
mal) address at which it is loaded. (The linux-vdso and ld-linux shared dependencies are special; see vdso(7) and ld.so(8).)
Security
Be aware that in some circumstances (e.g., where the program specifies an ELF interpreter other than ld-linux.so), some versions of ldd may
attempt to obtain the dependency information by attempting to directly execute the program, which may lead to the execution of whatever
code is defined in the program's ELF interpreter, and perhaps to execution of the program itself. (In glibc versions before 2.27, the
upstream ldd implementation did this for example, although most distributions provided a modified version that did not.)
Thus, you should never employ ldd on an untrusted executable, since this may result in the execution of arbitrary code. A safer alterna-
tive when dealing with untrusted executables is:
$ objdump -p /path/to/program | grep NEEDED
Note, however, that this alternative shows only the direct dependencies of the executable, while ldd shows the entire dependency tree of
the executable.
OPTIONS --version
Print the version number of ldd.
-v, --verbose
Print all information, including, for example, symbol versioning information.
-u, --unused
Print unused direct dependencies. (Since glibc 2.3.4.)
-d, --data-relocs
Perform relocations and report any missing objects (ELF only).
-r, --function-relocs
Perform relocations for both data objects and functions, and report any missing objects or functions (ELF only).
--help Usage information.
BUGS
ldd does not work on a.out shared libraries.
ldd does not work with some extremely old a.out programs which were built before ldd support was added to the compiler releases. If you
use ldd on one of these programs, the program will attempt to run with argc = 0 and the results will be unpredictable.
SEE ALSO pldd(1), sprof(1), ld.so(8), ldconfig(8)COLOPHON
This page is part of release 4.15 of the Linux man-pages project. A description of the project, information about reporting bugs, and the
latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.
2017-09-15 LDD(1)