Help on bash script?

[Xu Qiang]

dpk wrote:
> It will work with either 'let' or within an 'arithmetic expansion':
> 
> $[++var]
> let ++var
> 
> By the way, there is another syntax, from the man page, that seems to
> operate identically:
> 
> $((++var)) and $((var+1))

With "let ++var", the result is still 0, it isn't incremented. With $[++var], the result is "0: command not found".
"$((++var))" is to the same effect as "let ++var". 

$((var+1)) works. But the value of var can't be incremented. 

thanks, 
Xu Qiang