simple bash script to increment the version number of the format major.minor.bug

bump-version

#!/usr/bin/env bash

help () {
  echo "usage: ./bump-version version_number [major/minor/bug]"
}

# Check input remove prepending 'v'
if grep -q -c -E '^v?[[:digit:]]{1,3}\.[[:digit:]]{1,3}\.[[:digit:]]{1,3}$' <<< ${1}; then
  version=$(sed 's/^.\{1\}//g' <<< ${1})
else
  help
fi

major=0
minor=0
bug=0

# break down the version number into it's components
regex="([0-9]+).([0-9]+).([0-9]+)"
if [[ $version =~ $regex ]]; then
  major="${BASH_REMATCH[1]}"
  minor="${BASH_REMATCH[2]}"
  bug="${BASH_REMATCH[3]}"
fi

# check paramater to see which number to increment
if [[ "$2" == "major" ]]; then
  major=$(echo $major+1 | bc)
  minor=0
  bug=0
elif [[ "$2" == "minor" ]]; then
  minor=$(echo $minor + 1 | bc)
  bug=0
elif [[ "$2" == "bug" ]]; then
  bug=$(echo $bug + 1 | bc)
else
  help
  exit 1
fi

# echo the new version number
echo "${major}.${minor}.${bug}"