get_mainline_kernel (bash script,CODE)

#!/bin/bash
vars='?C=N;O=D'
mainline=http://kernel.ubuntu.com/~kernel-ppa/mainline/
arch=amd64
rm -r /tmp/k /tmp/md /tmp/mt 2>/dev/null
wget -O- ${mainline}$vars > /tmp/k
if [ -s /tmp/k ]
 then distrgx='/href=/{s/\(^.*href="\)\(v[^"]\+[a-z]\/\)\(".*\)/\2/p;}'
 tiprgx='/href=/{s/\(^.*href="\)\(v[^"]\+\/\)\(".*\)/\2/p;}'
 patrgx='s/\(^.*href="\)\([0-9].*\.patch\)\(".*$\)/\2/p'
 d=`sed -n -e $distrgx /tmp/k | head -n1`
 t=`sed -n -e $tiprgx /tmp/k | head -n1`
 echo d $d t $t
 wget -O- ${mainline}$d > /tmp/md
 wget -O- ${mainline}$t > /tmp/mt
 if [ -s /tmp/md ] && [ -s /tmp/mt ]
  then tpatches=( `sed -n -e $patrgx /tmp/mt | sort | uniq` )
  for (( n=0 ; n<${#tpatches[@]} ; n++ ))
   do tpatches[$n]=${mainline}${t}${tpatches[$n]}
  done
  deb='/href=/{/generic/{/'$arch'/{/image/s/\(^.*href="\)\([^"]\+\)\(".*\)/\2/p;};};}'
  headers='/href=/{/generic/{/'$arch'/{/headers/s/\(^.*href="\)\([^"]\+\)\(".*\)/\2/p;};};}'
  allhdrs='/href=/{/all/{/headers/s/\(^.*href="\)\([^"]\+\)\(".*\)/\2/p;};}'
  dist=${mainline}${d}`sed -n -e $deb /tmp/md | tail -n1`
  distheaders=${mainline}${d}`sed -n -e $headers /tmp/md | tail -n1`
  alld=${mainline}${d}`sed -n -e $allhdrs /tmp/md | tail -n1`
  tip=${mainline}${t}`sed -n -e $deb /tmp/mt | tail -n1`
  tipheaders=${mainline}${t}`sed -n -e $headers /tmp/mt | tail -n1`
  allt=${mainline}${t}`sed -n -e $allhdrs /tmp/mt | tail -n1`
  echo dist $dist
  echo distheaders $distheaders prereq all $alld
  echo tip $tip
  echo tipheaders $tipheaders prereq all $allt
  mkdir -p ~/Downloads/mainline
  pushd ~/Downloads/mainline 2>/dev/null
  rm *.deb *.patch # install headers first for grub mkinitramfs
  for f in $alld $distheaders $dist $allt $tipheaders $tip ${tpatches[@]}
   do ff=`echo $f | sed -e 's/^.*\///'`
   [ -s "$ff" ] || wget $f
   [ -n "$ff" ] && [ -f $ff ] && [ -s $ff ] && \
    [ $ff != ${ff%.deb} ] && sudo dpkg -i $ff
  done
  popd 2>/dev/null
 fi
fi
rm -r /tmp/k /tmp/md /tmp/mt 2>/dev/null