Linux Swap Space Mini-HOWTO: The swapinit.sh script

Next Previous Contents

## 9. The swapinit.sh script

This shell script initializes the swap space on the partition. The code for signature detection has been repeated 6 times because many a times the signature is properly detected only on the second or the third try.

(Adapted from the original Swap-Space-HOWTO by H. Peter Anvin)

> `

>     #!/bin/sh
>     #
>     # swapinit.sh - activate the swap partition
>     #
>     # written by Rahul U. Joshi
>     # Verify and initialize swap space
>     #

>     echo -n 'Verifying swap space... '

>     loopcount=0

>     # flag to indicate whether the partition has been activated or not
>     activated=0

>     # check for signatures 6 times before giving up
>     while [ $loopcount -lt 6 ]
>       do

>       if [ "`/bin/dd 2>/dev/null if=/dev/winswap bs=1 count=10  skip=4086`" = 'SWAP-SPACE' ]; then
>         echo "Linux signature found, iteration $loopcount"
>         echo "Activating swap partitions"
>         swapon /dev/winswap
>         activated=1
>         break

>       elif [ "`/bin/dd 2>/dev/null if=/dev/winswap bs=1 count=11 skip=43`" = 'SWAP SPACE ' ]; then
>         echo "DOS signature found, iteration $loopcount"
>         echo "Making swap partition"
>         mkswap /dev/winswap YYYYY
>         echo "Activating swap partitions"
>         swapon /dev/winswap
>         activated=1
>         break

>       else
>        let loopcount=loopcount+1
>       fi

>       done

>     if [ $activated -ne 1 ] ; then
>       echo "Swap signature not found after $loopcount tries"
>       echo "No swapping partitions activated"
>       exit 1
>     fi

> `

Next Previous Contents