Looks like I'm wrong. If I fire up an interactive dash on Ubuntu or Debian, no arrow keys. /bin/sh is dash, but that's only for hash bang scripts.
Not just no arrow keys, but nothing. No Ctrl-P to recall previous line. No editing beyond the POSIX TTY line discipline stuff: Ctrl-W word erase, Ctrl-U line erase, backspace.
also i'm wrong; it doesn't have an option to compile with readline, just libedit (which indeed is not included in the debian package configuration). the incantation was as follows:
on the other hand my dash process with libedit is 1.3 megs rss while my bash process is 7 megs rss. and the dash executable is only 130k. still, bash is only about 20% slower to start up
Not just no arrow keys, but nothing. No Ctrl-P to recall previous line. No editing beyond the POSIX TTY line discipline stuff: Ctrl-W word erase, Ctrl-U line erase, backspace.