Shortcut Keys

For bash:

cd -         Change to the previous working directory.
Esc + .      The last command line argument of the last comment
^w erase word 
^u erase from here to beginning of the line (I use this ALL the time.) 
^a move the cursor to the beginning of the line 
^e move the curor to the end of the line 

Bash - Read line

In recent versions of bash you can specify the maximum number of characters to read:

read -p "Erase the windows partition (Y/n)? " -n1

Convert filenames to lowercase

A simple script: tolower

Ranges in bash

function range () { 
    if [ $1 -ge $2 ]; then
        return
    fi
    a=$1
    b=$2
    while [ $a -le $b ]; do
        echo $a;
        a=$(($a+1));
    done
} 
> for i in $(range 1 5) ;do echo $i;done
1
2
3
4
5