Should it really be as terse as posix shell? If you think before you type, it's not a high-frequency REPL anymore.
cd foo/<tab>
# oh, too many options
<ret>
ls -la
cd bar/baz
git status
cat quux | grep xckd
cat quux | grep -i xckd
cat quux | grep -i xkcd
cat quux | grep -i xkcd | xargs ...
etc.The trial-and-error command refining is arguably what REPLs are for. It's the filesystem navigation that are the odd part.
(INB4: don't give me the "useless use of cat", it factors out better like this and everyone does it anyway.)
`<quux grep xkcd`