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 (hexadecimal) 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 infor-
       mation 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 alternative 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 sup-
       port 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)