"BashDiff extends the for, while, and until commands to include
optional then and else blocks following the main loop block. These
new optional then/else blocks let you perform an action after a
normal iteration of the block (the then block) and a block of
commands when the break command is used (the else block). Using the
else block is useful if you want to see if the loop was terminated
early using the break command.
"Bash 3 includes the sequence generation expression {1..100},
which expands to a space-separated sequence of the numbers between
1 and 100. In standard bash you cannot set these minimum and
maximum values using shell variables but must fall back to using
the seq command. BashDiff allows you to use variables, as the
following example shows:"