After seeing how to cycle through Terminal’s autocomplete options using the TAB key, here’s how to get rid of another minor annoyance (for some). The autocompletion in Terminal is case-sensitive; if you have a directory called Downloads in your home directory, writing

cd dow

and pressing TAB will not auto-complete to cd Downloads/ 

To remedy this for the current Terminal session only, run this:

set completion-ignore-case On

More likely though, you’ll want to make this permanent. Run these in Terminal (courtesy of this post):

# If ~./inputrc doesn't exist yet, first include the original /etc/inputrc so we don't override it
if [ ! -a ~/.inputrc ]; then echo "\$include /etc/inputrc" > ~/.inputrc; fi 

# Add option to ~/.inputrc to enable case-insensitive tab completion
echo "set completion-ignore-case On" >> ~/.inputrc

To change this for all users, edit /etc/inputrc and add this line:

set completion-ignore-case On

You might have to restart Terminal, but after that you’re set. Happy tabbing.