rename to pishrink,since we move this in /usr/local/bin and chmod a+x, add a Makefile

pishrink

@@ -0,0 +1,93 @@
+#!/bin/bash
+
+usage() { echo "Usage: $0 imagefile.img [newimagefile.img]"; exit -1; }
+
+#Args
+img="$1"
+
+#Usage checks
+if [[ -z "$img" ]]; then
+  usage
+fi
+if [[ ! -f "$img" ]]; then
+  echo "ERROR: $img is not a file..."
+  exit -2
+fi
+
+#Check that what we need is installed
+for command in tune2fs e2fsck resize2fs; do
+  which $command 2>&1 >/dev/null
+  if (( $? != 0 )); then
+    echo "ERROR: $command is not installed."
+    exit -4
+  fi
+done
+
+#Copy to new file if requested
+if [ -n "$2" ]; then
+  echo "Copying $1 to $2..."
+  cp "$1" "$2"
+  if (( $? != 0 )); then
+    echo "ERROR: Could not copy file..."
+    exit -5
+  fi
+  img="$2"
+fi
+
+#Gather info
+beforesize=$(ls -lh "$img" | tr -s " " | cut -d " " -f 5)
+partnum=$(fdisk "$img" | grep Linux | cut -d ":" -f1 | tr -d " ")
+partstart=$(fdisk -d "$img" | grep 0x83 | cut -d "," -f1)
+loopback=$(hdiutil attach -nomount "$img" | grep Linux | cut -d " " -f1)
+tune2fs_output=$(tune2fs -l "$loopback")
+currentsize=$(echo "$tune2fs_output" | grep '^Block count:' | tr -d ' ' | cut -d ':' -f 2)
+blocksize=$(echo "$tune2fs_output" | grep '^Block size:' | tr -d ' ' | cut -d ':' -f 2)
+
+#Make sure filesystem is ok, force yes on all questions
+e2fsck -y -f "$loopback"
+minsize=$(resize2fs -P "$loopback" | cut -d ':' -f 2 | tr -d ' ')
+
+# add ~200 MB of extra space, the system may need it to run
+minsize=$(($minsize + 50000))
+
+if [[ $minsize -gt $currentsize ]]; then
+echo "ERROR: Image already shrunk to smallest size"
+exit -6
+fi
+
+#Shrink filesystem
+resize2fs -p "$loopback" $minsize
+if [[ $? != 0 ]]; then
+  echo "ERROR: resize2fs failed..."
+  hdiutil detach $loopback
+  exit -7
+fi
+sleep 1
+
+#Shrink partition
+hdiutil detach $loopback
+# fdisk uses a block size of 512 Bytes!
+partnewsize=$(($minsize * $blocksize / 512))
+newpartend=$(($partstart + $partnewsize))
+
+# now use fdisk to change the partition
+fdisk -e "$img" <<EOF2
+e $partnum
+
+
+
+$newpartend
+w
+q
+
+EOF2
+sleep 1
+
+#Truncate the file
+endresult=$(($partnewsize + 1))
+dd if="$img" of="$img-shrinked.img" bs=512 count=$endresult
+aftersize=$(ls -lh "$img-shrinked.img" | tr -s " " | cut -d " " -f 5)
+rm -f "$img"
+mv "$img-shrinked.img" "$img"
+
+echo "Shrunk $img from $beforesize to $aftersize"