build-kernel

#!/bin/bash

NumCPU=$(grep -c ^processor /proc/cpuinfo)
NumJobs=$(calc -p "ceil(2*$NumCPU+1)")
export CONCURRENCY_LEVEL=$NumJobs

baseURL="https://www.kernel.org/pub/linux/kernel/v3.x/"
latest="$(curl -s $baseURL | sed -n 's|\(.*\)\(linux-\)\(.*\)\(\.tar\.xz<\)\(.*\)|\3|p' | sort --version-sort | tail -n1)"

[ ! "$latest" ]  &&  { echo "Are we offline?" >&2; exit 1; }

echo "latest version: $latest"
echo -n "Build this? [(y)/n] "

read -n1 ans
echo

if [ ! "$ans" ] || [ "$ans" = y ] || [ "$ans" = Y ] || [ "$ans" = j ]  || [ "$ans" = J ]
then
    version="$latest"
else
    echo -n "Enter kernel version to build: "
    read version
    echo
fi

stableURL="${baseURL}linux-${version}.tar.xz"
testingURL="${baseURL}testing/linux-${version}.tar.xz"

prevDir="$(pwd)"
cd /tmp

echo attempting to download "${stableURL}"
echo

if ! wget -c "${stableURL}"
then
    echo "error downloading ${stableURL}"
    echo "Now trying to retrieve from ${testingURL} ..."
    echo
    wget -c "${testingURL}" || { echo "error downloading ${testingURL}" >&2; exit 1; }
fi

echo Extract...
tar -xJf linux-${version}.tar.xz || { echo "error extracting linux-${version}.tar.xz" >&2; exit 1; }

cd linux-${version}

make-kpkg clean || { echo "error out" >&2; exit 1; }

echo
echo -n "Start with build config from $(uname -r)? [(y)/n] "
read -n1 ans
echo

if [ ! "$ans" ] || [ "$ans" = y ] || [ "$ans" = Y ] || [ "$ans" = j ]  || [ "$ans" = J ]
then
    cp /boot/config-$(uname -r)  .config
else
    echo -n "Enter a full path to the desired base config file: "
    read ans
    [ -f "$ans" ] || { echo "File does not exist" >&2; exit 1; }
    echo "cp \"$ans\" .config"
    cp "$ans" .config
fi

make xconfig || { echo "error with xconfig" >&2; exit 1; }
#make menuconfig || { echo "error with menuconfig" >&2; exit 1; }

echo -n "what to append to kernel version? "
read buildName
[ "$buildName" ] || { echo "You must provide a string." >&2; exit 1; }

echo -n "Kernel revision? (choose a number) "
read myRevision
[ "$myRevision" ] || { echo "You must provide a string." >&2; exit 1; }

# Compile with some kind of minimal priority for I/O and CPU (ionice/schedtool).
#
# "eatmydata" does what it says in case of power blackout or so, because data
# is not necessarily written to disk (but still only in RAM). The benefit however
# is speed, because we do not need to wait for fsyncs()s.
ionice -c2 -n7 schedtool -D -n19 -e fakeroot eatmydata make-kpkg --append-to-version "-${buildName}" --revision "$myRevision" --initrd kernel_image kernel_headers  || { echo "error during build" >&2; exit 1; }
# find . -type f -exec cachedel '{}' \;  &>  /dev/null

cd ..

echo "install anything from $(ls -1 linux*${buildName}*.deb) (on your Desktop)"
mv linux*${buildName}*.deb  ${HOME}/Desktop

# remove kernel source directory
[ -d linux-${version} ]   &&   rm -rf linux-${version}

cd "$prevDir"