# ldd

## 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.
           (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**.
    
           **--verbose**
           **-v** Print all information, including, for example, symbol
                  versioning information.
    
           **--unused**
           **-u** Print unused direct dependencies.  (Since glibc 2.3.4.)
    
           **--data-relocs**
           **-d** Perform relocations and report any missing objects (ELF
                  only).
    
           **--function-relocs**
           **-r** 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.
    


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