This question is related to https://askubuntu.com/q/826288/295286 In my search online, I could find no mention of whether bash 3.2 comes with readline support. Thus, I would like to know, if there is a systematic way of finding out what libraries bash uses.
In the linked question , I used locate to search for readline.so ,but that approach seems a bit unreliable to me.
This is probably a duplicate (I recall it being answered). But:
For example:
$ ldd /bin/bash
linux-vdso.so.1 (0x00007ffeae9a5000)
libncurses.so.5 => /lib/x86_64-linux-gnu/libncurses.so.5 (0x00007fe9bc832000)
libtinfo.so.5 => /lib/x86_64-linux-gnu/libtinfo.so.5 (0x00007fe9bc608000)
libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007fe9bc403000)
libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007fe9bc062000)
/lib64/ld-linux-x86-64.so.2 (0x000055a30b725000)
On the other hand, the dependency in Debian/testing upon libncurses.so.5 is unnecessary (bash uses only the termcap interface which is provided by libtinfo.so.5).
If you want to see that bash uses readline, use nm -D (Linux...) to see the symbol table:
$ nm -D /bin/bash |grep readline
00000000006ffab0 B bash_readline_initialized
00000000006fce00 B current_readline_line
00000000006fcdf8 B current_readline_line_index
00000000006fce08 B current_readline_prompt
000000000046d600 T initialize_readline
0000000000475400 T pcomp_set_readline_variables
000000000046d360 T posix_readline_initialize
000000000049a450 T readline
0000000000499d30 T readline_internal_char
0000000000499300 T readline_internal_setup
0000000000499430 T readline_internal_teardown
00000000006f7910 D rl_gnu_readline_p
00000000006fca20 D rl_readline_name
00000000007003f8 B rl_readline_state
00000000006f7914 D rl_readline_version
The external symbols (essentially the same approach) show these entrypoints for the termcap interface:
U tgetent
U tgetflag
U tgetnum
U tgetstr
U tgoto
U tputs
(some people become confused by the libncurses dependency and suppose that bash uses ncurses — termcap applications are a special case).
