bash regex to match semantic version number

Question

I have the following:

versionNumber=$(sw_vers -productVersion) # Finds version number

versionShort=${versionNumber:0:4}  # Cut string to 1 decimal place for calculation

which works when versions are like this:

10.9.2
10.9.5

but it will not match

10.10.3

as it will return only

10.1

but I want the versionShort to be set to

10.10

I am wanting to match the major version, the first dot and the minor version as above.

score 16 · Answer 1 · answered Jun 20 '14 at 02:09

16

Regexpless solution - cut off last dot and whatever follows it:

versionShort=${versionNumber%.*}

answered Jun 20 '14 at 02:09

Amadan

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Careful, this doesn't work when using semver versions with a prerelease suffix like `10.9.5-rc.1` – Chris Jul 12 '22 at 08:07

Aleks-Daniel Jakimenko-A. · Answer 2 · 2014-06-20T15:23:07.223

13

Regexp solution:

[[ $versionNumber =~ ^[0-9]+\.[0-9]+ ]] && echo "${BASH_REMATCH[0]}"

It will always print first two numbers, for example all these:

10.5
10.5.9
10.5.8.2

Will result in 10.5 output. You can also add an else clause to check if something wrong happened (no match found).

Here is a longer version:

if [[ $versionNumber =~ ^[0-9]+\.[0-9]+ ]]; then
    versionShort=${BASH_REMATCH[0]}
else
    echo "Something is wrong with your version" >&2
fi

edited Jun 20 '14 at 15:23

answered Jun 20 '14 at 03:11

Aleks-Daniel Jakimenko-A.

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how do i return the result to a variable? – lukemh Jun 20 '14 at 05:49
@lukemh I have added a longer version that might be clearer for you. If it does not work... are you sure that you're using bash? If yes, then which version? In version 3 you have to put right side of the conditional expression into a variable. – Aleks-Daniel Jakimenko-A. Jun 20 '14 at 15:27
1

[semantic version](http://semver.org) tags must have exactly 3 numbers. – Mike Samuel May 08 '17 at 16:46
@MikeSamuel yes, that's right. Feel free to edit the answer. I wish it was easier to delete it altogether, but mentioning ``BASH_REMATCH`` is a worthy goal, even with a bad answer like this. – Aleks-Daniel Jakimenko-A. May 08 '17 at 21:51
… or write your own, and I'll delete mine :) – Aleks-Daniel Jakimenko-A. May 08 '17 at 21:52

score 13 · Answer 3 · answered Mar 09 '16 at 21:40

13

I had a similar question, but I needed access to all 3 segments. I did a bit of research and testing and I found this to work well

product_version=$(sw_vers -productVersion)
semver=( ${product_version//./ } )
major="${semver[0]}"
minor="${semver[1]}"
patch="${semver[2]}"
echo "${major}.${minor}.${patch}"

To answer this question directly, you could

product_version=$(sw_vers -productVersion)
semver=( ${product_version//./ } )
major="${semver[0]}"
minor="${semver[1]}"
patch="${semver[2]}"
versionShort="${major}.${minor}"

or you can use less variables

product_version=$(sw_vers -productVersion)
semver=( ${product_version//./ } )
versionShort="${semver[0]}.${semver[1]}"

answered Mar 09 '16 at 21:40

n8felton

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1

How does "semver=( ${product_version//./ } )" work? I unfortunately get semver="10.11.6//./" when I try this. – Jason Harrison Apr 27 '17 at 18:29
2

@JasonHarrison the code works by replacing dot "." with space " ", and then taking all the arguments as a bash array. In order for it to work you need to assign the semver text to a variable first. For example, `a="10.11.6"; semver=( ${a//./ } )` – VasiliNovikov Sep 18 '18 at 08:50

score 9 · Answer 4 · answered May 25 '18 at 12:49

https://github.com/fsaintjacques/semver-tool https://github.com/fsaintjacques/semver-tool/blob/master/src/semver

SEMVER_REGEX="^(0|[1-9][0-9]*)\\.(0|[1-9][0-9]*)\\.(0|[1-9][0-9]*)(\\-[0-9A-Za-z-]+(\\.[0-9A-Za-z-]+)*)?(\\+[0-9A-Za-z-]+(\\.[0-9A-Za-z-]+)*)?$"


function validate-version {
  local version=$1
  if [[ "$version" =~ $SEMVER_REGEX ]]; then
    # if a second argument is passed, store the result in var named by $2
    if [ "$#" -eq "2" ]; then
      local major=${BASH_REMATCH[1]}
      local minor=${BASH_REMATCH[2]}
      local patch=${BASH_REMATCH[3]}
      local prere=${BASH_REMATCH[4]}
      local build=${BASH_REMATCH[5]}
      eval "$2=(\"$major\" \"$minor\" \"$patch\" \"$prere\" \"$build\")"
    else
      echo "$version"
    fi
  else
    error "version $version does not match the semver scheme 'X.Y.Z(-PRERELEASE)(+BUILD)'. See help for more information."
  fi
}

Note: this snippet contains code that is licensed under GNU GPL v3: https://github.com/fsaintjacques/semver-tool/blob/master/LICENSE — ItalyPaleAle, Jun 04 '20 at 06:19

bash regex to match semantic version number

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