ldd

Linux 中 ldd(List Dynamic Dependencies) 可以列出可执行程序的动态库依赖关系，常用来查看可执行程序运行所需的共享库，在解决程序依赖关系中使用的比较多。

help

$ ldd --help
Usage: ldd [OPTION]... FILE...
      --help              print this help and exit
      --version           print version information and exit
  -d, --data-relocs       process data relocations
  -r, --function-relocs   process data and function relocations
  -u, --unused            print unused direct dependencies
  -v, --verbose           print all information

For bug reporting instructions, please see:
<http://www.gnu.org/software/libc/bugs.html>.

demo

查看 Nginx 的动态依赖库：

$ ldd /usr/sbin/nginx
	linux-vdso.so.1 =>  (0x00007ffed8993000)
	libdl.so.2 => /lib64/libdl.so.2 (0x00007fad30627000)
	libpthread.so.0 => /lib64/libpthread.so.0 (0x00007fad3040b000)
	libcrypt.so.1 => /lib64/libcrypt.so.1 (0x00007fad301d4000)
	libpcre.so.1 => /lib64/libpcre.so.1 (0x00007fad2ff72000)
	libssl.so.1.1 => /lib64/libssl.so.1.1 (0x00007fad2fce2000)
	libcrypto.so.1.1 => /lib64/libcrypto.so.1.1 (0x00007fad2f7ff000)
	libz.so.1 => /lib64/libz.so.1 (0x00007fad2f5e9000)
	libprofiler.so.0 => /lib64/libprofiler.so.0 (0x00007fad2f3d5000)
	libc.so.6 => /lib64/libc.so.6 (0x00007fad2f008000)
	/lib64/ld-linux-x86-64.so.2 (0x00007fad30b70000)
	libfreebl3.so => /lib64/libfreebl3.so (0x00007fad2ee05000)
	libstdc++.so.6 => /lib64/libstdc++.so.6 (0x00007fad2eafe000)
	libm.so.6 => /lib64/libm.so.6 (0x00007fad2e7fc000)
	libgcc_s.so.1 => /lib64/libgcc_s.so.1 (0x00007fad2e5e6000)