Bash can save you time when typing repeated strings by 'generating' strings for you, when given a range ({1..10}) or list of strings ({a,b,c}). It'll take the preambles and postscripts (characters immediately before and after the braces) and generate a set of strings using the brace contents.
Running echo {1..5} will result in 1 2 3 4 5
Running echo a{1,5,9}b will result in a1b a5b a9b
Braces can be combined, so echo {A,B,C}{0,1,2} will result in A0 A1 A2 B0 B1 B2 C0 C1 C2
They can also be nested, so echo {{0..9},{A..F}} will result in 0 1 2 3 4 5 6 7 8 9 A B C D E F
Downloading multiple files with wget:
wget http://raw.githubusercontent.com/github/gitignore/master/{Global/macOS,Node}.gitignore -O - >> .gitignore
Initializing files:
touch {index,app}.js