How to split a shell command over multiple lines (when using an IF statement) ?

Source https://stackoverflow.com/questions/18599711/how-can-i-split-a-shell-command-over-multiple-lines-when-using-an-if-statement

$ cat test.sh
if ! fab --fabfile=.deploy/fabfile.py \
   --forward-agent \
   --disable-known-hosts deploy:$target; then
     echo failed
else
     echo succeeded
fi

$ alias fab=true; . ./test.sh
succeeded
$ alias fab=false; . ./test.sh
failed