how can I test two strings against one variable using IF

Question

I want to test if the $ip is equal to one of the two values: "a" or "b". When I test against only "a" it works. I didn`t want to do || and perform another grep+cut, since I have done those once, I would like to take the result and test it against these 2 values.

if [[ $(grep -e "$ip" FILE |cut -d' ' -f5) =~ 'a\|b'; then
 echo "OK"
fi

Could you add the language in the question tags as this is obviously not language-agnostic? — Lionel
– Lionel, Commented Mar 14, 2016 at 15:13

glenn jackman · Accepted Answer · 2016-03-14 17:50:02Z

3

You don't have to do another grep+cut, you can always assign the result to a variable. Regex match is not equivalent to equality check. The following will be more readable

var=...; if [[ "$var" = "a" || "$var" = "b" ]]; then echo OK; fi

edited Mar 14, 2016 at 17:50

glenn jackman

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answered Mar 14, 2016 at 15:25

karakfa

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2 Comments

chepner Over a year ago

You can also use [[ $var = @(a|b) ]]; versions of bash prior to 4.1 will require running shopt -s extglob first to allow the extended pattern syntax.

karakfa Over a year ago

didn't know this thanks, actually better to convey intention.

glenn jackman · Accepted Answer · 2016-03-14 17:50:16Z

0

A case statement is a readable alternative

case "$(grep ...)" in
    a|b) 
        echo OK
        ;;
    *)
        echo not OK
        ;;
esac

answered Mar 14, 2016 at 17:50

glenn jackman

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