Hi,
how to write an if statement for values in between

if [$? -ne 0];then

fi

here I want to write an if statement if $? is inbetween 1 and 126
how to write this
if [$? inbetween 1 and 126];then
fi


I'd also like to know the difference between the following two if statements
if [$? -ne 0];then
fi
and
if [[$? -ne 0]];then
fi
Thanks for your time.
Ram

Depends on which shell you are using. The "[" version of test is the original one and tends to be an external program. Newer shells have "[[" which is a built in one and thus more efficient. You might also have "((" which is specifically for numeric stuff which means that you can use normal numeric comparisons rather than -ne, -eq etc.

To do an "in between" test with any of the above you need to use AND or OR depending on which way round you do it. AND is && and OR is ||


e.g.

if [ $val -lt 127 ] && [ $val -gt 0 ]
then
......

fi



there might be niftier ways with some shells (like doing the && or || inside a single test ) but it depends what you are using.

We were posting at the same time.


Hmmm...I was curious about those double ampersands and pipes I've seen as well.

Thanks.

For the in-between question:

if [ $? -ge 1 -a $? -le 126 ] ; then
...
fi


For the what's the difference question:
I'm kinda curious about that too.

This is the Bourne shell syntax:

And this is the Korn shell syntax:

The -a and -o clauses can not be used inside the Korn shell-specific test statement.

Regards

Oh. I get it. Kinda. Just another way to confuse us.

Thanks for the info (except I thought I'm using the Korn shell...)

The Bourne syntax is still valid in Korn, but not vice versa. In other words, Korn shell is backwards-compatible with the "classic" Bourne shell.

Just for completeness, [ test1 ] && [ test2 ] is valid Bourne syntax too.