These methods create an image file that is equal to the total capacity of the SD card. For example, cloning an SD card with a capacity of 32GB will create an image file of 32 GB, even if only 5 GB is actually in use on the card. This is fine if you only have one or two such images, but any more than that (especially if you use an SSD) will cause you to run out of space. Unfortunately, this tool is only available on Linux. If you do not have Linux installed, you can install the latest version of Ubuntu or Linux Mint in a virtual machine, and run this script there:
#!/bin/bash
usage() { echo "Usage: $0 [-s] imagefile.img [newimagefile.img]"; exit -1; }
should_skip_autoexpand=false
while getopts ":s" opt; do
case "${opt}" in
s) should_skip_autoexpand=true ;;
*) usage ;;
esac
done
shift $((OPTIND-1))
#Args
img=$1
#Usage checks
if [[ -z $img ]]; then
usage
fi
if [[ ! -e $img ]]; then
echo "ERROR: $img is not a file..."
exit -2
fi
if (( EUID != 0 )); then
echo "ERROR: You need to be running as root."
exit -3
fi
#Check that what we need is installed
A=`which parted 2>&1`
if (( $? != 0 )); then
echo "ERROR: parted is not installed."
exit -4
fi
#Copy to new file if requested
if [ -n "$2" ]; then
echo "Copying $1 to $2..."
cp --reflink=auto --sparse=always "$1" "$2"
if (( $? != 0 )); then
echo "ERROR: Could not copy file..."
exit -5
fi
img=$2
fi
#Gather info
beforesize=`ls -lah $img | cut -d ' ' -f 5`
partnum=`parted -m $img unit B print | tail -n 1 | cut -d ':' -f 1 | tr -d '\n'`
partstart=`parted -m $img unit B print | tail -n 1 | cut -d ':' -f 2 | tr -d 'B\n'`
loopback=`losetup -f --show -o $partstart $img`
currentsize=`tune2fs -l $loopback | grep 'Block count' | tr -d ' ' | cut -d ':' -f 2 | tr -d '\n'`
blocksize=`tune2fs -l $loopback | grep 'Block size' | tr -d ' ' | cut -d ':' -f 2 | tr -d '\n'`
#Check if we should make pi expand rootfs on next boot
if [ "$should_skip_autoexpand" = false ]; then
#Make pi expand rootfs on next boot
mountdir=`mktemp -d`
mount $loopback $mountdir
if [ `md5sum $mountdir/etc/rc.local | cut -d ' ' -f 1` != "a27a4d8192ea6ba713d2ddd15a55b1df" ]; then
echo Creating new /etc/rc.local
mv $mountdir/etc/rc.local $mountdir/etc/rc.local.bak
###Do not touch the following 6 lines including EOF###
cat <<\EOF > $mountdir/etc/rc.local
#!/bin/bash
/usr/bin/raspi-config --expand-rootfs
rm -f /etc/rc.local; cp -f /etc/rc.local.bak /etc/rc.local; reboot
exit 0
EOF
###End no touch zone###
chmod +x $mountdir/etc/rc.local
fi
umount $mountdir
else
echo Skipping autoexpanding process...
fi
#Make sure filesystem is ok
e2fsck -f $loopback
minsize=`resize2fs -P $loopback | cut -d ':' -f 2 | tr -d ' ' | tr -d '\n'`
if [[ $currentsize -eq $minsize ]]; then
echo ERROR: Image already shrunk to smallest size
exit -6
fi
#Add some free space to the end of the filesystem
if [[ `expr $currentsize - $minsize - 5000` -gt 0 ]]; then
minsize=`expr $minsize + 5000 | tr -d '\n'`
elif [[ `expr $currentsize - $minsize - 1000` -gt 0 ]]; then
minsize=`expr $minsize + 1000 | tr -d '\n'`
elif [[ `expr $currentsize - $minsize - 100` -gt 0 ]]; then
minsize=`expr $minsize + 100 | tr -d '\n'`
fi
#Shrink filesystem
resize2fs -p $loopback $minsize
if [[ $? != 0 ]]; then
echo ERROR: resize2fs failed...
mount $loopback $mountdir
mv $mountdir/etc/rc.local.bak $mountdir/etc/rc.local
umount $mountdir
losetup -d $loopback
exit $rc
fi
sleep 1
#Shrink partition
losetup -d $loopback
partnewsize=`expr $minsize \* $blocksize | tr -d '\n'`
newpartend=`expr $partstart + $partnewsize | tr -d '\n'`
part1=`parted $img rm $partnum`
part2=`parted $img unit B mkpart primary $partstart $newpartend`
#Truncate the file
endresult=`parted -m $img unit B print free | tail -1 | cut -d ':' -f 2 | tr -d 'B\n'`
truncate -s $endresult $img
aftersize=`ls -lah $img | cut -d ' ' -f 5`
echo "Shrunk $img from $beforesize to $aftersize"$ chmod +x ./shrink.sh
$ sudo ./shrink.sh ./some-image.img