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)