Version of ppa-purge with a way of skipping updating the packages on every run

ppa-purge

#!/bin/bash
# A script to remove all packages in a PPA and revert back to the normal
# distribution ones.
#
# AUTHORS: Robert Hooker (Sarvatt), Tormod Volden

# Defaults
F_ARCHS=$(dpkg --print-foreign-architectures)
PPA_PKGS=$(mktemp)
REVERTS=$(mktemp)
trap "rm $PPA_PKGS $REVERTS" 0

# Functions to write output nicely.
write_msg() {
    echo "$*" | fold -s -w "${COLUMNS:-80}"
}

msg() {
    write_msg "$*"
}

warn() {
    write_msg "Warning:  $*" 1>&2
}

usage() {
    echo "Usage: sudo ppa-purge [options] <ppa:ppaowner>[/ppaname]"
    echo
    echo "ppa-purge will reset all packages from a PPA to the standard"
    echo "versions released for your distribution."
    echo
    echo "Options:"
    echo "	-p [ppaname]		PPA name to be disabled (default: ppa)"
    echo "	-o [ppaowner]		PPA owner"
    echo "	-s [host]		Repository server (default: ppa.launchpad.net)"
    echo "	-d [distribution]	Override the default distribution choice."
    echo "	-y 			Pass "-y --force-yes" to apt-get or "-y" to aptitude"
    echo "	-i			Reverse preference of apt-get upon aptitude."
    echo "	-S			Skip updating the mirrors."
    echo "	-h			Display this help text"
    echo
    echo "Example usage commands:"
    echo "	sudo ppa-purge -o xorg-edgers"
    echo "	will remove https://launchpad.net/~xorg-edgers/+archive/ppa"
    echo
    echo "	sudo ppa-purge -o sarvatt -p xorg-testing"
    echo "	will remove https://launchpad.net/~sarvatt/+archive/xorg-testing"
    echo
    echo "	sudo ppa-purge [ppa:]ubuntu-x-swat/x-updates"
    echo "	will remove https://launchpad.net/~ubuntu-x-swat/+archive/x-updates"
    echo
    echo "Notice: If ppa-purge fails for some reason and you wish to try again,"
    echo "(For example: you left synaptic open while attempting to run it) simply"
    echo "uncomment the PPA from your sources, run apt-get update and try again."
    echo
    exit $1
}


# Command line options
while getopts "p:o:s:d:ySih\?" opt; do
    case "$opt" in
        p ) PPANAME="$OPTARG";;
        o ) PPAOWNER="$OPTARG";;
        s ) PPAHOST="$OPTARG";;
        d ) DIST="$OPTARG";;
        y ) FORCEINSTALL="true";;
        S ) DO_UPDATE="false";;
        i ) APTALT="true";;
        h ) usage 0;;
        \?) usage 1;;
        * ) warn "Unknown option '$opt'"; usage 1;;
    esac
done
shift $(($OPTIND -1))

if [ -z "$PPAOWNER" ]; then
    PPAOWNER=$1
fi

APTARG=""
if [ ! -z "$APTALT" ]; then
    if [ ! -z "$FORCEINSTALL" ]; then
    APTARG="-y"
    fi
    APT=aptitude; APTALT=apt-get
else
    if [ ! -z "$FORCEINSTALL" ]; then
    APTARG="-y --force-yes"
    fi
    APT=apt-get; APTALT=aptitude
fi

if echo $1 | grep -q "^ppa:"; then
    PPAOWNER=$(echo $1 | sed "s#^ppa:\(.*\)/\(.*$\)#\1#")
    PPANAME=$(echo $1 | sed "s#^ppa:\(.*\)/\(.*$\)#\2#")
else
    if echo $1 | grep -q "^.*/.*$"; then
        PPAOWNER=$(echo $1 | sed "s#^\(.*\)/\(.*$\)#\1#")
        PPANAME=$(echo $1 | sed "s#^\(.*\)/\(.*$\)#\2#")
    fi
fi

if [ -z "$PPAOWNER" ]; then
    warn "Required ppa-name argument was not specified"
    usage 1
fi

# If not set, using defaults
[ -z "$PPAHOST" ] && PPAHOST="ppa.launchpad.net"
[ -z "$PPANAME" ] && PPANAME="ppa"
[ -z "$DIST" ] && DIST=$(lsb_release -c -s)

if [ "$(id -u)" != "0" ]; then
    warn "This script would need superuser privileges, use sudo"
    usage 1
fi


if [ -z "$DO_UPDATE" ]; then
    msg "Updating packages lists"
    if ! $APT update > /dev/null; then
        warn "$APT update failed for some reason"
        exit 1
    fi
else
    msg "Skipping update of mirrors"
fi

msg "PPA to be removed: $PPAOWNER $PPANAME"

# Make list of all packages in PPA
PPA_LIST=/var/lib/apt/lists/${PPAHOST}_${PPAOWNER}_${PPANAME}_*_Packages
for LIST in $PPA_LIST; do
    if [ -e $LIST ]; then
        grep "^Package: " $LIST | cut -d " " -f2 | sort >> $PPA_PKGS
    fi
done

if [ ! -s $PPA_PKGS ]; then
    warn "Could not find package list for PPA: $PPAOWNER $PPANAME"
    exit 1
fi

# Ignore the ppa-purge package
if grep -q "ppa-purge" $PPA_PKGS; then
    sed -i '/ppa-purge/d' $PPA_PKGS
    msg "Note: Not removing ppa-purge package"
fi

# Get multi-arch package names for revert list
cat $PPA_PKGS | sort -u |
    xargs dpkg-query -W -f='${binary:Package}\t${db:Status-Abbrev}\n' 2>/dev/null |
    awk '/\tii $/{print $1}' > $REVERTS
# Fallback for Precise
if [ ! -s $REVERTS ]; then
    for PACKAGE in $(cat $PPA_PKGS | sort -u); do
        dpkg-query -W -f='${PackageSpec}\t${Status}\n' $PACKAGE 2>/dev/null |
            awk '/\tinstall/{print $1}' >> $REVERTS
        for F_ARCH in $F_ARCHS; do
            dpkg-query -W -f='${PackageSpec}\t${Status}\n' "$PACKAGE:$F_ARCH" 2>/dev/null |
                awk '/\tinstall/{print $1}' >> $REVERTS
        done
    done
fi

# Create apt argument list for reverting packages
REINSTALL=""
for PACKAGE in $(cat $REVERTS); do
    AVAIL=$(apt-cache policy $PACKAGE | grep -v "$PPAHOST/$PPAOWNER/$PPANAME" | grep -c "500.*$DIST"  )
    if [ $AVAIL -eq 0 ]; then
        REINSTALL="$REINSTALL $PACKAGE-"
    else
        REINSTALL="$REINSTALL $PACKAGE/$DIST"
    fi
done

msg "Package revert list generated:"
msg "$REINSTALL"
echo

# Disable PPA from sources.list files
for LIST in $(find /etc/apt/ -name "*.list" -exec readlink -f '{}' \;); do
    if [ -e $LIST ] && grep -q $PPAOWNER/$PPANAME $LIST; then
        msg "Disabling $PPAOWNER PPA from $LIST"
        sed -ri "\:^[^#]+/${PPAOWNER}/${PPANAME}/:s/^deb/# deb/" $LIST
    fi
done

msg "Updating packages lists"
$APT update > /dev/null || warn "$APT update failed for some reason"

# FIXME:
# Workaround for now in case APT fails because of missing dependencies.

if $APT $APTARG install $REINSTALL; then
    msg "PPA purged successfully"
elif $APTALT $APTARG install $REINSTALL; then
    msg "PPA purged successfully using $APTALT fallback"
else
    warn "Something went wrong, packages may not have been reverted"
    exit 1
fi
exit 0