1LDD(1)                     Linux Programmer's Manual                    LDD(1)
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NAME

6       ldd - print shared object dependencies
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SYNOPSIS

9       ldd [option]... file...
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DESCRIPTION

12       ldd  prints the shared objects (shared libraries) required by each pro‐
13       gram or shared object specified on the command line.  An example of its
14       use and output is the following:
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16         $ ldd /bin/ls
17                 linux-vdso.so.1 (0x00007ffcc3563000)
18                 libselinux.so.1 => /lib64/libselinux.so.1 (0x00007f87e5459000)
19                 libcap.so.2 => /lib64/libcap.so.2 (0x00007f87e5254000)
20                 libc.so.6 => /lib64/libc.so.6 (0x00007f87e4e92000)
21                 libpcre.so.1 => /lib64/libpcre.so.1 (0x00007f87e4c22000)
22                 libdl.so.2 => /lib64/libdl.so.2 (0x00007f87e4a1e000)
23                 /lib64/ld-linux-x86-64.so.2 (0x00005574bf12e000)
24                 libattr.so.1 => /lib64/libattr.so.1 (0x00007f87e4817000)
25                 libpthread.so.0 => /lib64/libpthread.so.0 (0x00007f87e45fa000)
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27       In  the  usual  case,  ldd  invokes  the  standard  dynamic linker (see
28       ld.so(8)) with the LD_TRACE_LOADED_OBJECTS environment variable set  to
29       1.   This  causes  the  dynamic linker to inspect the program's dynamic
30       dependencies, and find (according to the rules described  in  ld.so(8))
31       and  load the objects that satisfy those dependencies.  For each depen‐
32       dency, ldd displays the location of the matching object and the  (hexa‐
33       decimal)  address  at which it is loaded.  (The linux-vdso and ld-linux
34       shared dependencies are special; see vdso(7) and ld.so(8).)
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36   Security
37       Be aware that in some circumstances (e.g., where the program  specifies
38       an  ELF  interpreter  other than ld-linux.so), some versions of ldd may
39       attempt to obtain the dependency information by attempting to  directly
40       execute  the  program, which may lead to the execution of whatever code
41       is defined in the program's ELF interpreter, and perhaps  to  execution
42       of  the  program  itself.  (In glibc versions before 2.27, the upstream
43       ldd implementation did this for example,  although  most  distributions
44       provided a modified version that did not.)
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46       Thus,  you  should  never  employ ldd on an untrusted executable, since
47       this may result in the execution of arbitrary code.  A  safer  alterna‐
48       tive when dealing with untrusted executables is:
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50           $ objdump -p /path/to/program | grep NEEDED
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52       Note, however, that this alternative shows only the direct dependencies
53       of the executable, while ldd shows the entire dependency  tree  of  the
54       executable.
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OPTIONS

57       --version
58              Print the version number of ldd.
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60       -v, --verbose
61              Print all information, including, for example, symbol versioning
62              information.
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64       -u, --unused
65              Print unused direct dependencies.  (Since glibc 2.3.4.)
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67       -d, --data-relocs
68              Perform relocations and report any missing objects (ELF only).
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70       -r, --function-relocs
71              Perform relocations for both data  objects  and  functions,  and
72              report any missing objects or functions (ELF only).
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74       --help Usage information.
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BUGS

77       ldd does not work on a.out shared libraries.
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79       ldd  does  not  work  with some extremely old a.out programs which were
80       built before ldd support was added to the compiler  releases.   If  you
81       use  ldd on one of these programs, the program will attempt to run with
82       argc = 0 and the results will be unpredictable.
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SEE ALSO

85       pldd(1), sprof(1), ld.so(8), ldconfig(8)
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COLOPHON

88       This page is part of release 4.16 of the Linux  man-pages  project.   A
89       description  of  the project, information about reporting bugs, and the
90       latest    version    of    this    page,    can     be     found     at
91       https://www.kernel.org/doc/man-pages/.
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95                                  2017-09-15                            LDD(1)
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