CODEWITHSUNDEEP
regexbashdash-shell
Marco Ceppi
Marco Ceppi

Reputation: 7702

How to regex compare a string in dash?

I'm moving a bash script to dash for compatibility reasons. Is there a POSIX/Dash alternative to the following comparison?

COMPARE_TO="^(lp:~?|https?://|svn://|svn\+ssh://|bzr://|bzr\+ssh://|git://|ssh://)"

if [[ $COMPARE =~ $COMPARE_TO ]]; then
    echo "WE ARE COMPARED!"
fi

Upvotes: 5

Views: 5529

Answers (2)

Gordon Davisson
Gordon Davisson

Reputation: 125788

dash doesn't have regex comparing built in, but you can always use grep:

if echo "$compare" | egrep -q "$compare_to"; then
    ...

(Note that I second @geirha's note about uppercase variables in the shell.)

Upvotes: 6

geirha
geirha

Reputation: 6181

You can use a case. It doesn't use regex, but it's not that much longer with globs

case $compare in
    lp:*|http://*|https://*|svn://*|svn+ssh://*|bzr://*|bzr+ssh://*|git:/*|ssh://*)
        echo "We are compared"
    ;;
esac

On a side note, you should avoid using all uppercase variable names as you risk overwriting special shell variables or environment variables.

Upvotes: 10

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