Korn Shell test if multiple variables are set

jonlake · 04-09-2008, 09:03 AM

I'm writing a script in korn shell and cannot figure how to do the following:

In bash, it works like

Code:

#!/bin/bash

A="stuff"
B="more stuff"

if [[ -n $A && -n $B ]]; then
        echo "A is set to $A and B is set to $B"
else
        echo "A or B is not set"
fi

Results in

Code:

A is set to stuff and B is set to more stuff

Unfortunately, I don't have bash available in the environment I'm working in and don't know how to do this in ksh.
In ksh, I get

Code:

[[: ./test.sh  expression syntax error
A or B is not set

edit: I also tried

Code:

if [[ $A != "" && $B != "" ]]

but it didn't like a space in B

tronayne · 04-09-2008, 09:39 AM

Uh, this:

Code:

#!/bin/ksh
A="stuff"
B="more stuff"

if [[ -n $A && -n $B ]]; then
        echo "A is set to $A and B is set to $B"
else
        echo "A or B is not set"
fi

produces

Code:

A is set to stuff and B is set to more stuff

Isn't that what you want?

Look and see if your login shell is sh or ksh, maybe.

jonlake · 04-09-2008, 09:51 AM

Sorry, I don't think I was clear. I posted the bash script I had made because I know bash just a little better than ksh. In my ksh script, I have #!/bin/ksh at the top, so I have:

Code:

#!/bin/ksh

A="stuff"
B="more stuff"

if [[ -n $A && -n $B ]]; then
        echo "A is set to $A and B is set to $B"
else
        echo "A or B is not set"
fi

and it returns

Code:

[[: ./test.sh  expression syntax error
A or B is not set

as apparently bash and ksh treat test differently?

More specifically, I am using the MKS toolkit which installs ksh, csh, tcl shell, and other stuff to run in windows.

edit:
apparently it is this toolkit I am using, because I just installed ksh on my gentoo laptop and ran the script in ksh, and it runs as expected, but when ran from the toolkit's korn shell, the if test fails and outputs:

Code:

[[: ./test.sh  expression syntax error
A or B is not set

Yet, if I test just one variable, it will run as expected.

tronayne · 04-09-2008, 10:20 AM

Ah, winders (well, maybe).

OK, here's another way to do conditionals

Code:

if [ -n "${A}" -a -n "${B}" ]

(the braces are not necessary, but are a good habit to get into; with this syntax, the quotes should be used)

Try that and see if it works for you.

jonlake · 04-09-2008, 10:41 AM

Adding the braces and quotes worked.

Thanks