How to test if variable is in specified format in Bash?

Question

My Bash script accepts an argument of a version number, in the following format: #.#.#.#.dev or #.#.#.#.prod, where # can be any number, for example: 3.6.212.0.dev.

I want to verify that the argument is in the right format (contains all the 4 numbers separated by dots and includes .prod or .dev in the end).

I'm not sure how to achieve this, so far I've tried this:

re='^[0-9]+$'
if ! [[ $1 =~ $re ]] ; then
echo "error: Incorrect version specified; must be in the format of #.#.#.#.env" >&2; exit 1
fi

Wiktor Stribiżew · Accepted Answer · 2021-04-02 19:27:54Z

3

You can use

re='^([0-9]+\.){4}(dev|prod)$'
if ! [[ "$1" =~ $re ]] ; then
  echo "error: Incorrect version specified; must be in the format of #.#.#.#.env" >&2; exit 1
fi

See a Bash demo online.

^([0-9]+\.){4}(dev|prod)$ is a POSIX ERE compliant pattern that matches:

^ - start of string
([0-9]+\.){4} - four occurrences of one or more digits and a dot
(dev|prod) - dev or prod substring
$ - end of string.

answered Apr 2, 2021 at 19:27

Wiktor Stribiżew

631k41 gold badges502 silver badges632 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Gilbert Williams Over a year ago

Thank you! The part where you explain about each part of the Regex is really helpful for newbies like myself!

Collectives™ on Stack Overflow

How to test if variable is in specified format in Bash?

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related