[ILUG] quoting bash strings

[Niall O Broin]

On 10 Dec 2010, at 14:15, Braun Brelin wrote:

> Does anyone know the reason why I have to quote strings when testing them
> like so?
> 
> s1="foo"
> 
> if [ -n "$s1" ]; then
>   echo blah
> fi
> 
> i.e. why the "$s1" in the test expression?  Anyone know the answer?

You don't "have" to do it, but if you don't, you'll get an error when $1 isn't set because

if [ -n ] ; then

is syntactically incorrect

while

if [ -n "" ]; then


is not.


Niall