#!/bin/bash# Two ways to count up to 10.echo# Standard syntax.for a in 1 2 3 4 5 6 7 8 9 10do  echo -n "$a "done  echo; echo# +==========================================+# Now, let's do the same, using C-like syntax.LIMIT=10for ((a=1; a <= LIMIT ; a++))  # Double parentheses, and "LIMIT" with no "$".do  echo -n "$a "done                           # A construct borrowed from 'ksh93'.echo; echo# +=========================================================================+# Let's use the C "comma operator" to increment two variables simultaneously.for ((a=1, b=1; a <= LIMIT ; a++, b++))  # The comma chains together operations.do  echo -n "$a-$b "doneecho; echoexit 0