Public SourceMage Discussion List

[Juuso Alasuutari <iuso AT sourcemage.org>]

I wrote a function that checks if current kernel version is equal or newer 
than a given one. It checks the version in any scale, whether >=2.6 or 
>=2.6.15 or >=2.6.15.4, etc., and it strips chars beginning from - 
(2.6.16-some_norse_god --> 2.6.16).

It could be used to selectively apply patches that fix kernel update issues. 
At the moment at least two spells do that kind of checking (in a rudimentary 
way), svgalib and nvidia_driver. (They're in diff grimoires, though, so I 
don't know if the definition "needed by several spells" is fulfilled for this 
to go into FUNCTIONS...)

Of course it could also be used to negatively check whether kernel ver is too 
recent.

Here's the code, tell me what's wrong with it.

function is_kernel_minimum() {
  local MIN CUR a b n=1
  MIN=`expr $1 : '\(^[^-]*\)'`
  MIN=${MIN//\./\ }
  CUR=`get_kernel_version`
  CUR=`expr $CUR : '\(^[^-]*\)'`
  CUR=${CUR//\./\ }
  for a in $MIN; do
    b=`echo $CUR | cut -d" " -f$n`
    if (( a < b )); then
      return 0
    elif (( a > b )); then
      return 1
    fi
    (( n += 1 ))
  done
}

Juuso