How to mass-rename tags and push them with Git

gistfile1.txt

# Rename tags named foo-bar-#.#.# to v#.#.# and push the tag changes
git tag -l | while read t; do n="v${t##*-}"; git tag $n $t; git push --tags ; git tag -d $t; git push origin :refs/tags/$t ; done

This changes x.y.z to x/y/z, but won't delete tags that are already in new format

# make sure your tags are up to date
git fetch origin
# rename all tags
git tag -l | while read t; do n=$(echo $t | sed "s?\.?/?g"); if [[ "$n" != "$t" ]]; then git tag $n $t; git tag -d $t; git push origin :refs/tags/$t ; done

This changes build/n to build/0n (e.g.: build/8 -> build/08).

git tag -l | while read t; do n=$(echo $t | sed "s?\/?/0?g"); git tag $n $t; git tag -d $t; done

Rename all vx.y.z tags to x.y.z:
git tag -l | while read t; do n="${t#?}"; git tag $n $t; git push --tags ; git tag -d $t; git push origin :refs/tags/$t ; done

Don't forget to turn off CI/CD, if it's based on the tags ;)

If you have a mixture of vx.y.z and x.y.z tags, the first command will add a v to your existing 'v' tags, creating vvx.y.z tags...

This shell script solves that issue:

#!/bin/bash

# Get all of the repo's tags
all_tags=$(git tag)

# Loop through all tags
for tag in $all_tags; do
    # Only process tags not starting with "v"
    if [[ $tag != v* ]]; then
        # Create the vx.y.z tag
        git tag v$tag $tag
        # Delete the x.y.z tag
        git tag -d $tag
        # Pushes the new vx.y.z tag and deletes the x.y.z tag remotely
        git push origin  v$tag :$tag
    fi
done

# Push all tags, shouldn't be necessary, just there as backup
git push --tags