ldd

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 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
       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 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 5.04 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/.



                                  2019-03-06                            LDD(1)