usage of "echo $[3=2]"

tianlijian · 11-24-2008, 09:48 PM

What does "$[]" means? Is it arithemetic expansion? if it is, why i can not find the usgae in the man pages?

colucix · 11-25-2008, 12:23 AM

Yes, it is an arithmetic operator (quite obsolete and obscure I believe). You can find some example on the Advanced Bash Scripting Guide, example 8.2. In the example you have posted, maybe you want to evaluate a condition and get a value which is 0 or 1 depending on the result, false or true. But in that case it should be

Code:

echo $[3==2]

colucix · 11-25-2008, 12:24 AM

Edit: double posting, my mistake... sorry.