Merge pull request #9 from cskiraly/master

make PiShrink work on/from SD

README.md

@@ -1,13 +1,15 @@
 # PiShrink #
-PiShrink is a bash script that automatically shrink a pi image that will then resize to the max size of the SD card on boot. This will make putting the image back onto the SD card faster and the shrunk images will compress better.
+PiShrink is a bash script that automatically shrink a pi image that will then resize to the max size of the SD card on boot. This will make putting the image back onto the SD card faster and the shrunk images will compress better. The script can also work directly from the SD card reader device.
 
-`Usage: ./pishrink [-s] imagefile.img [newimagefile.img]`
+`Usage: ./pishrink [-s] [-i] imagefile.img [newimagefile.img]`
+        ./pishrink [-s] [-i] /dev/sd_device [newimagefile.img]`
 
 If the `-s` option is given the script will skip the autoexpanding part of the process.  If you specify the `newimagefile.img` parameter, the script will make a copy of `imagefile.img` and work off that. You will need enough space to make a full copy of the image to use that option.
+If a device file (e.g. /dev/mmcblk0) is given as parameter, it will shrink the image directly on the SD card. If the `-i` option is given the script will first shrink in place, then prepare a copy. This is especially useful when the first parameter is a device file and space is limited.
 
 ## Example ##
 ```bash
-[user@localhost PiShrink]$ sudo ./shrink.sh pi.img
+[user@localhost PiShrink]$ sudo ./pishrink.sh pi.img
 e2fsck 1.42.9 (28-Dec-2013)
 Pass 1: Checking inodes, blocks, and sizes
 Pass 2: Checking directory structure
@@ -28,6 +30,32 @@ The filesystem on /dev/loop1 is now 773603 blocks long.
 
 Shrunk pi.img from 30G to 3.1G
 ```
+## Example: copying shrinking directly from SD ##
+
+[user@localhost PiShrink]$ sudo  ./pishrink.sh /dev/mmcblk0 pi.img
+Copying /dev/mmcblk0 to pi.img...
+30528+0 records in
+30528+0 records out
+32010928128 bytes (32 GB, 30 GiB) copied, 587,625 s, 54,5 MB/s
+Creating new /etc/rc.local
+e2fsck 1.42.13 (17-May-2015)
+Pass 1: Checking inodes, blocks, and sizes
+Pass 2: Checking directory structure
+Pass 3: Checking directory connectivity
+Pass 4: Checking reference counts
+Pass 5: Checking group summary information
+/dev/loop0: 127844/1915424 files (0.1% non-contiguous), 1743616/7798016 blocks
+resize2fs 1.42.13 (17-May-2015)
+resize2fs 1.42.13 (17-May-2015)
+Resizing the filesystem on /dev/loop0 to 2187260 (4k) blocks.
+Begin pass 3 (max = 238)
+Scanning inode table          XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
+The filesystem on /dev/loop0 is now 2187260 (4k) blocks long.
+Shrunk pi.img from 30G to 8,5G
+
+## Example: shrinking directly on SD ad copying ##
+
+
 
 ## Contributing ##
 If you find a bug please create an issue for it. If you would like a new feature added, you can create an issue for it but I can't promise that I will get to it.

pishrink.sh

@@ -1,12 +1,14 @@
 #!/bin/bash
 
-usage() { echo "Usage: $0 [-s] imagefile.img [newimagefile.img]"; exit -1; }
+usage() { echo "Usage: $0 [-s] [-i] imagefile.img [newimagefile.img]"; exit -1; }
 
 should_skip_autoexpand=false
+force_inplace_and_copy_after=false
 
-while getopts ":s" opt; do
+while getopts ":s:i" opt; do
   case "${opt}" in
     s) should_skip_autoexpand=true ;;
+    i) force_inplace_and_copy_after=true ;;
     *) usage ;;
   esac
 done
@@ -36,9 +38,15 @@ if (( $? != 0 )); then
 fi
 
 #Copy to new file if requested
-if [ -n "$2" ]; then
+if [ -n "$2" -a "$force_inplace_and_copy_after" = false ]; then
   echo "Copying $1 to $2..."
-  cp --reflink=auto --sparse=always "$1" "$2"
+  if [[ -f $img ]]; then
+    cp --reflink=auto --sparse=always "$1" "$2"
+  else
+    imgsize=`parted -m $img unit B print | tail -1 | cut -d ':' -f 3 | tr -d 'B\n'`
+    imgsize=`expr $imgsize + 1`
+    dd if="$1" of="$2" conv=sparse count=$imgsize iflag=count_bytes bs=1M
+  fi
   if (( $? != 0 )); then
     echo "ERROR: Could not copy file..."
     exit -5
@@ -150,8 +158,27 @@ 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'`
+if [[ -f $img ]]; then
-truncate -s $endresult $img
+  endresult=`parted -m $img unit B print free | tail -1 | cut -d ':' -f 2 | tr -d 'B\n'`
-aftersize=`ls -lah $img | cut -d ' ' -f 5`
+  truncate -s $endresult $img
+  aftersize=`ls -lah $img | cut -d ' ' -f 5`
+  echo "Shrunk $img from $beforesize to $aftersize"
+fi
 
-echo "Shrunk $img from $beforesize to $aftersize"
+#Copy to new file if requested
+if [ -n "$2" -a "$force_inplace_and_copy_after" = true ]; then
+  echo "Copying $1 to $2..."
+  if [[ -f $img ]]; then
+    cp --reflink=auto --sparse=always "$1" "$2"
+  else
+    imgsize=`parted -m $img unit B print | tail -1 | cut -d ':' -f 3 | tr -d 'B\n'`
+    imgsize=`expr $imgsize + 1`
+    dd if="$1" of="$2" conv=sparse count=$imgsize iflag=count_bytes bs=1M
+  fi
+
+  if (( $? != 0 )); then
+    echo "ERROR: Could not copy file..."
+    exit -5
+  fi
+  img=$2
+fi