rootninja

In a shell script you’re probably testing a variable against some constant or another variable, but why not run a command in a subshell and compare the output?  You could even compare the output of two subshell commands!  I guess most of the time i’m doing something like this i’m using perl or python.  But I needed a way to double check which disk had a powerpc boot partition on it before copying it over to a blank disk and I didn’t have much to work with on those old boards, so I whipped this up right quick:

#!/bin/sh

#check to see if sda has a PPC boot partition

if [ "`/sbin/fdisk -l /dev/sda | grep PPC`" == "" ]; then

if [ "`/sbin/fdisk -l /dev/sdb | grep PPC`" == "" ]; then

echo “both disks have PPC boot partitions”

exit 1;

else

echo “run this: dd if=/dev/sdb of=/dev/sda”

fi

else

if [ "`/sbin/fdisk -l /dev/sdb | grep PPC`" == "" ]; then

echo “run this: dd if=/dev/sda of=/dev/sdb”

else

echo “both disks have PPC boot partitions”

exit 1;

fi

fi

Shell scripting if-then-else tests with commands embedded in backticks.  Why?  Because i’m messing with some old power pc blades running 2.4 kernels with no modern day apps like ssh, rsync, or python.  I don’t know why I didn’t think of this before now?

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