Gentoo Updater Script

#!/bin/bash

# Copyright (C) 2014 Alexander Mohn <pogrmman+dev@gmail.com>
# Permission is hereby granted, free of charge, to any person obtaining a copy of this script to use it without restriction,
# including without limitation of the rights to use, copy, modify, merge, publish, distribute, and/or sublicense this script
# subject to the following conditions:
# The above copyright notice and this permission notice shall be included in all copies or substantial portions of this
# script.
# THIS SCRIPT IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
# WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHOR
# BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
# ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THIS SCRIPT.

# This script provides a way to update and maintain your Gentoo system
# with a single command.


####### Functions #######

# This updates the portage tree.
function sync
{
    read -p "Press [Enter] to update the portage tree..."
    sudo emerge --sync
}

# This logs the old python version.
function python_old
{
    mkdir /tmp/update
    eselect python list > /tmp/update/python_old.lst                                    # Makes a list of old python versions.
    awk '{print $2}' < /tmp/update/python_old.lst > /tmp/update/python_old              # Extracts version names.
    python_old=($(cat /tmp/update/python_old))
    pyv2_old=${python_old[1]}
    pyv3_old=${python_old[2]}
    echo $pyv2_old > /tmp/update/pyv2_old
    echo $pyv3_old > /tmp/update/pyv3_old
    cut -c 9 /tmp/update/pyv2_old > /tmp/update/v2_old                                  # Converts version names into numbers.
    cut -c 9 /tmp/update/pyv3_old > /tmp/update/v3_old
    pyv2_old=($(cat /tmp/update/v2_old))
    pyv3_old=($(cat /tmp/update/v3_old))
}

# This logs the new python version.
function python_new
{
    eselect python list > /tmp/update/python.lst                                            # Lists new versions of python.
    awk '{print $2}' < /tmp/update/python.lst > /tmp/update/python                      # Extracts the version names.
    py=($(cat /tmp/update/python))
    pyv2=${py[1]}
    pyv3=${py[2]}
    echo $pyv2 > /tmp/update/pyv2
    echo $pyv3 > /tmp/update/pyv3
    cut -c 9 /tmp/update/pyv2 > /tmp/update/v2                                          # Converts the version names into numbers.
    cut -c 9 /tmp/update/pyv3 > /tmp/update/v3
    pyv2=($(cat /tmp/update/v2))
    pyv3=($(cat /tmp/update/v3))
}

# This updates the system.
function update
{
    read -p "Press [Enter] key to begin updating system..."
    python_old
    sudo emerge --ask --update --deep --with-bdeps=y --newuse @world
    python_new
    if [ "$pyv2_old" != "$pyv2" ]; then
        read -p "Press [Enter] key to fix files broken by Python 2.x update..."
        sudo python-updater
    fi
    if [ "$pyv3_old" != "$pyv3" ]; then
        read -p "Press [Enter] key to fix files broken by Python 3.x update..."
        sudo python-updater
    fi
}

# This changes any configuration files that must be updated.
function config
{
    read -p "Press [Enter] key to change configuration files..."
    sudo dispatch-conf
}
# This checks for broken packages.
function pkg_check
{
    read -p "Press [Enter] key to check for broken packages..."
    sudo revdep-rebuild -p
}

# This rebuilds broken packages.
function pkg_rebuild
{
    read -p "Press [Enter] key to rebuild broken packages..."
    sudo revdep-rebuild
}

# This removes obsolete packages.
function clean
{
    read -p "Press [Enter] key to remove obsolete packages..."
    sudo emerge --ask --depclean --with-bdeps=y
}

# This prints introductory text.
function intro
{
    cat <<- _INTRO_
    Welcome to the system updater.
    You may be asked to enter your password several times during the process.
    If you do not have sudo privilages for emerge, revdep-rebuild, dispatch-conf,
    python-updater, and perl-cleaner this script may fail.
    _INTRO_
}

# If no options are specified.
function noopts
{
    cat <<- _DESC_
    This script helps to keep your Gentoo system up to date.
    You must specify at least one option.
    USAGE: update [-option1] [-option2] [-option3] [-option4] [-option5] [-option6]

            -S Sync the portage tree.
            -U Update the system.
            -C Change config files.
            -P Check for broken packages.
            -p Rebuild broken packages.
            -D Remove obsolete packages and dependenicies.
            -h Display this help text.

    WARNING: Options will be parsed in the order in which they are given.
    It is generally wise to use -S before -U, -U before -D, and -D before -p.
    _DESC_
}

####### End of Function Declarations #######

####### Main #######

if [ "$1" = "" ]; then                                                                  # Checks to see if any options are specified.
    noopts                                                                              # If not, it displays usage.
else
    if [ "$1" = "-h" ]; then                                                            # Checks to see if -h is specified.
        noopts                                                                          # If it is, it displays usage.
    else
        intro                                                                           # Display introductory text.
        while [ "$1" != "" ]; do                                                        # Option parser.
            case $1 in
                -h ) noopts ;;
                -S ) sync ;;
                -U ) update ;;
                -C ) config ;;
                -P ) pkg_check ;;
                -p ) pkg_rebuild ;;
                -D ) clean ;;
            esac
            shift
        done                                                                    # End of option parser.
        echo "Done updating system!"
    fi
fi
rm -r /tmp/update
exit 0

####### End #######