Check if parameter does NOT match regex with two possible values?

Question

Here is what I'm trying to do in one of my bash scripts.

If SERVER_ENV is not PROD or TEST, the script must exit.

check-server-env() {
  local SERVER_ENV="$1"
  if ! [[ "$SERVER_ENV"^^ =~ ^(TEST|PROD)$ ]]; then
    error "$(highlight "$SERVER_ENV")" " does not exist."
    echo "Exiting script..."
    echo ""
    exit 0
  fi
}

I call script.sh TEST

SERVER_ENV=$1

check-server-env $SERVER_ENV

Here is how I'm calling. And it's not working. What am I doing wrong?

The regex is not necessary. You can just do if [ "$SERVER_ENV" != TEST ] && [ "$SERVER_ENV" != PROD ]; then .... — Shane Bishop
– Shane Bishop, Commented Feb 16, 2021 at 15:42
@ShaneBishop I guess it would also work. But I'd like to do it using regex. Thanks! — cbdeveloper
– cbdeveloper, Commented Feb 16, 2021 at 15:45
As pointed out by @anubhava, that's the wrong way to make a string uppercase in bash. The correct way is "${SERVER_ENV^^}" (note the { and }). — Shane Bishop
– Shane Bishop, Commented Feb 16, 2021 at 15:45
Also I don't understand regex tag removal rationale. If OP wants a regex help what's wrong with having it in question? — anubhava
– anubhava, Commented Feb 16, 2021 at 15:52

Shane Bishop · Accepted Answer · 2021-02-17 06:18:07Z

6

You may use:

check-server-env() {
  local SERVER_ENV="$1"

  if [[ ! "${SERVER_ENV^^}" =~ ^(TEST|PROD)$ ]]; then
    error "$(highlight "$SERVER_ENV")" " does not exist."
    echo "Exiting script..."
    echo ""
    exit 0
  fi
}

However you may ditch regex and use extglob matching in bash:

check-server-env() {
  local SERVER_ENV="$1"

  if [[ "${SERVER_ENV^^}" != @(TEST|PROD) ]]; then
    error "$(highlight "$SERVER_ENV")" " does not exist."
    echo "Exiting script..."
    echo ""
    exit 0
  fi
}

edited Feb 17, 2021 at 6:18

Shane Bishop

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answered Feb 16, 2021 at 15:43

anubhava

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Comments

MonkeyZeus · Accepted Answer · 2021-02-16 15:52:07Z

1

Why use regex at all?

if [ "${SERVER_ENV^^}" != "PROD" ] && [ "${SERVER_ENV^^}" != "TEST" ]; then
    error "$(highlight "$SERVER_ENV")" " does not exist."
    echo "Exiting script..."
    echo ""
    exit 0
fi

edited Feb 16, 2021 at 15:52

answered Feb 16, 2021 at 15:45

MonkeyZeus

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3 Comments

Shane Bishop Over a year ago

This condition won't match the OP's desired logic.

MonkeyZeus Over a year ago

@ShaneBishop thanks for catching that, fixed!

Shane Bishop Over a year ago

Still not fixed - you need &&. Quoting the OP: "If SERVER_ENV is not PROD or TEST, the script must exit." Here the English language is being ambiguous, but the English "not ... or" in this case translates to && in bash, because of De Morgan's law. (The English sentence translates to "not (x or y)", which De Morgan's law translates to "(not x) and (not y)").

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