ldd - tracking used libraries/versions

To figure out what libraries(and its location/version as well) an executable is using hit it with "ldd". When using it know in mind that it needs the exact path to the executable.

For example to track down what "ls" is using try this

~> ldd /bin/ls
       linux-vdso.so.1 =>  (0x00007fffdfad4000)
       librt.so.1 => /lib/librt.so.1 (0x00007f33ad7a1000)
       libselinux.so.1 => /lib/libselinux.so.1 (0x00007f33ad585000)
       libacl.so.1 => /lib/libacl.so.1 (0x00007f33ad37e000)
       libc.so.6 => /lib/libc.so.6 (0x00007f33ad01c000)
       libpthread.so.0 => /lib/libpthread.so.0 (0x00007f33ace00000)
       /lib64/ld-linux-x86-64.so.2 (0x00007f33ad9aa000)
       libdl.so.2 => /lib/libdl.so.2 (0x00007f33acbfc000)
       libattr.so.1 => /lib/libattr.so.1 (0x00007f33ac9f8000)