Create an ".inputrc" file in the user's home directory.
touch .inputrc
Case-sensitive auto-completion
vim .inputrc
Enter set completion-ignore-case on
:wq
save and exit
Display all possible choices
vim .inputrc
Enter set show-all-if-ambiguous on
:wq
save and exit
In fact, this command can be used to do it all.
cat >> ".inputrc" << EOF
set completion-ignore-case on
set show-all-if-ambiguous on
EOF