ldd(1)                                                                                               General Commands 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 exe‐
       cute 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.  (Before glibc 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)

Linux man‐pages 6.03                                                                                       2023‐02‐05                                                                                                     ldd(1)