显示指定程序的依赖库，例如：
[root@localhost bin]# ldd redis-cli
linux-vdso.so.1 => (0x00007ffc41f4e000)
libm.so.6 => /lib64/libm.so.6 (0x00007f83a3e75000)
libdl.so.2 => /lib64/libdl.so.2 (0x00007f83a3c71000)
libpthread.so.0 => /lib64/libpthread.so.0 (0x00007f83a3a55000)
libc.so.6 => /lib64/libc.so.6 (0x00007f83a3688000)
/lib64/ld-linux-x86-64.so.2 (0x00007f83a4177000)
帮助信息如下：
[root@localhost bin]# 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.