grep highest semantic version from stdin

grepsemver

#!/bin/bash -e

print_help() {
    cat <<EOF
Usage: cat versions.txt | $0 [OPTIONS]

Options:
  --major             Output major version of the latest semver
  --minor             Output minor version of the latest semver
  --patch             Output patch version of the latest semver
  --increase-major    Increment major version (resets minor and patch to 0)
  --increase-minor    Increment minor version (resets patch to 0)
  --increase-patch    Increment patch version
  --help              Show this help message

Grep the highest semantic version from stdin and apply options to it. Without options its just printed. It exits
with 1 when no semantic version is found.
EOF
}

which -s egrep sort bc head

# Check if stdin is empty
if [ -t 0 ]; then
    print_help
    exit 1
fi

# Read and parse latest version
LATEST_VERSION=$(egrep '^[0-9]+\.[0-9]+\.[0-9]+$' | sort -Vr | head -n 1)

# Validate the latest version
if ! [[ "$LATEST_VERSION" =~ ^[0-9]+\.[0-9]+\.[0-9]+$ ]]; then
    echo "No semver version in input detected." >&2
    exit 1
fi

# Split version
IFS='.' read -r MAJOR MINOR PATCH <<< "$LATEST_VERSION"

# Parse arguments
while [[ $# -gt 0 ]]; do
    case "$1" in
        --major)
            echo "$MAJOR"
            exit 0
            ;;
        --minor)
            echo "$MINOR"
            exit 0
            ;;
        --patch)
            echo "$PATCH"
            exit 0
            ;;
        --increase-major)
            ((MAJOR++))
            MINOR=0
            PATCH=0
            ;;
        --increase-minor)
            ((MINOR++))
            PATCH=0
            ;;
        --increase-patch)
            ((PATCH++))
            ;;
        --help)
            print_help
            exit 0
            ;;
        *)
            echo "Unknown option: $1" >&2
            print_help
            exit 1
            ;;
    esac
    shift
done

# Output final version
echo "$MAJOR.$MINOR.$PATCH"