Rabin2 is able to find imported objects by an executable, as well as their offsets in its PLT. This information is useful, for example, to understand what external function is invoked by call instruction. Pass -i flag to rabin2 to get a list of imports. An example:
$ rabin2 -i /bin/ls
[Imports]
1 0x000032e0 GLOBAL FUNC __ctype_toupper_loc
2 0x000032f0 GLOBAL FUNC getenv
3 0x00003300 GLOBAL FUNC sigprocmask
4 0x00003310 GLOBAL FUNC __snprintf_chk
5 0x00003320 GLOBAL FUNC raise
6 0x00000000 GLOBAL FUNC free
7 0x00003330 GLOBAL FUNC abort
8 0x00003340 GLOBAL FUNC __errno_location
9 0x00003350 GLOBAL FUNC strncmp
10 0x00000000 WEAK NOTYPE _ITM_deregisterTMCloneTable
11 0x00003360 GLOBAL FUNC localtime_r
12 0x00003370 GLOBAL FUNC _exit
13 0x00003380 GLOBAL FUNC strcpy
14 0x00003390 GLOBAL FUNC __fpending
15 0x000033a0 GLOBAL FUNC isatty
16 0x000033b0 GLOBAL FUNC sigaction
17 0x000033c0 GLOBAL FUNC iswcntrl
18 0x000033d0 GLOBAL FUNC wcswidth
19 0x000033e0 GLOBAL FUNC localeconv
20 0x000033f0 GLOBAL FUNC mbstowcs
21 0x00003400 GLOBAL FUNC readlink
...
