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...
10

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

58       --version
59              Print the version number of ldd.
60
61       -v, --verbose
62              Print all information, including, for example, symbol versioning
63              information.
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65       -u, --unused
66              Print unused direct dependencies.  (Since glibc 2.3.4.)
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68       -d, --data-relocs
69              Perform relocations and report any missing objects (ELF only).
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71       -r, --function-relocs
72              Perform relocations for both data objects and functions, and re‐
73              port any missing objects or functions (ELF only).
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75       --help Usage information.
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BUGS

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

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

89       This  page  is  part of release 5.10 of the Linux man-pages project.  A
90       description of the project, information about reporting bugs,  and  the
91       latest     version     of     this    page,    can    be    found    at
92       https://www.kernel.org/doc/man-pages/.
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96                                  2019-03-06                            LDD(1)
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