• Ruby (up is a simple Ruby one-liner)

wget -O /usr/bin/up https://raw.github.com/woongy/up/master/up

and then add alias up="source /usr/bin/up" to .bashrc and/or .bash_profile

• Jump to the nearest parent directory

    /foo/bar/baz/qux $ up foo
    /foo $
  

• Case-insensitive match by default

    /fOo/bar/baz/qux $ up FoO
    /foo $
  

• Match by first characters

    /foo/bar/baz/qux $ up fo
    /foo $
  

• up with no arguments works like cd ..

    /foo/bar/baz/qux $ up
    /foo/bar/baz $
  

• up to / does not work (but we already have cd / for that)

    /foo $ up /     # error
    /foo $ up       # stays at /foo