ldd(1)



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 pro-
       gram 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 depen-
       dency, ldd displays the location of the matching object and the  (hexa-
       decimal)  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)

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