From 9d6392d0c2e71f0e2b1d7d8a7bde7ba09d5c0cc1 Mon Sep 17 00:00:00 2001
From: Andrew Scheller <github@loowis.durge.org>
Date: Mon, 22 Jan 2018 01:23:54 +0000
Subject: [PATCH 01/12] Use $() for command-substitution instead of backticks

---
 pishrink.sh | 44 ++++++++++++++++++++++----------------------
 1 file changed, 22 insertions(+), 22 deletions(-)

diff --git a/pishrink.sh b/pishrink.sh
index 19ec060..11f4771 100755
--- a/pishrink.sh
+++ b/pishrink.sh
@@ -29,7 +29,7 @@ if (( EUID != 0 )); then
 fi
 
 #Check that what we need is installed
-A=`which parted 2>&1`
+A=$(which parted 2>&1)
 if (( $? != 0 )); then
   echo "ERROR: parted is not installed."
   exit -4
@@ -47,20 +47,20 @@ if [ -n "$2" ]; then
 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 $loopback | grep 'Block size' | tr -d ' ' | cut -d ':' -f 2 | tr -d '\n'`
+beforesize=$(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 [ "$should_skip_autoexpand" = false ]; then
   #Make pi expand rootfs on next boot
-  mountdir=`mktemp -d`
+  mountdir=$(mktemp -d)
   mount $loopback $mountdir
 
-  if [ `md5sum $mountdir/etc/rc.local | cut -d ' ' -f 1` != "0542054e9ff2d2e0507ea1ffe7d4fc87" ]; then
+  if [ $(md5sum $mountdir/etc/rc.local | cut -d ' ' -f 1) != "0542054e9ff2d2e0507ea1ffe7d4fc87" ]; then
     echo Creating new /etc/rc.local
     mv $mountdir/etc/rc.local $mountdir/etc/rc.local.bak
     #####Do not touch the following lines#####
@@ -132,19 +132,19 @@ fi
 
 #Make sure filesystem is ok
 e2fsck -p -f $loopback
-minsize=`resize2fs -P $loopback | cut -d ':' -f 2 | tr -d ' ' | tr -d '\n'`
+minsize=$(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'`
+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
@@ -161,14 +161,14 @@ 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 $newpartend`
+partnewsize=$(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 "$img" unit B print free | tail -1 | cut -d ':' -f 2 | tr -d 'B\n'`
+endresult=$(parted -m "$img" unit B print free | tail -1 | cut -d ':' -f 2 | tr -d 'B\n')
 truncate -s $endresult "$img"
-aftersize=`ls -lah "$img" | cut -d ' ' -f 5`
+aftersize=$(ls -lah "$img" | cut -d ' ' -f 5)
 
 echo "Shrunk $img from $beforesize to $aftersize"

From b11de9a8ee01f9ff9cb7c6fcff8d18dcb5b48716 Mon Sep 17 00:00:00 2001
From: Andrew Scheller <github@loowis.durge.org>
Date: Mon, 22 Jan 2018 01:34:46 +0000
Subject: [PATCH 02/12] Remove unused variables

---
 pishrink.sh | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/pishrink.sh b/pishrink.sh
index 11f4771..1b464a1 100755
--- a/pishrink.sh
+++ b/pishrink.sh
@@ -29,7 +29,7 @@ if (( EUID != 0 )); then
 fi
 
 #Check that what we need is installed
-A=$(which parted 2>&1)
+which parted 2>&1 >/dev/null
 if (( $? != 0 )); then
   echo "ERROR: parted is not installed."
   exit -4
@@ -163,8 +163,8 @@ sleep 1
 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 $newpartend)
+parted "$img" rm $partnum >/dev/null
+parted "$img" unit B mkpart primary $partstart $newpartend >/dev/null
 
 #Truncate the file
 endresult=$(parted -m "$img" unit B print free | tail -1 | cut -d ':' -f 2 | tr -d 'B\n')

From b787dd4e66511af274e9230a18039691034e0376 Mon Sep 17 00:00:00 2001
From: Andrew Scheller <github@loowis.durge.org>
Date: Mon, 22 Jan 2018 01:37:05 +0000
Subject: [PATCH 03/12] Always quote echo strings

---
 pishrink.sh | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/pishrink.sh b/pishrink.sh
index 1b464a1..847caa9 100755
--- a/pishrink.sh
+++ b/pishrink.sh
@@ -61,7 +61,7 @@ if [ "$should_skip_autoexpand" = false ]; then
   mount $loopback $mountdir
 
   if [ $(md5sum $mountdir/etc/rc.local | cut -d ' ' -f 1) != "0542054e9ff2d2e0507ea1ffe7d4fc87" ]; then
-    echo Creating new /etc/rc.local
+    echo "Creating new /etc/rc.local"
     mv $mountdir/etc/rc.local $mountdir/etc/rc.local.bak
     #####Do not touch the following lines#####
 cat <<\EOF1 > $mountdir/etc/rc.local
@@ -127,14 +127,14 @@ EOF1
   fi
   umount $mountdir
 else
-  echo Skipping autoexpanding process...
+  echo "Skipping autoexpanding process..."
 fi
 
 #Make sure filesystem is ok
 e2fsck -p -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
+  echo "ERROR: Image already shrunk to smallest size"
   exit -6
 fi
 
@@ -150,7 +150,7 @@ fi
 #Shrink filesystem
 resize2fs -p $loopback $minsize
 if [[ $? != 0 ]]; then
-  echo ERROR: resize2fs failed...
+  echo "ERROR: resize2fs failed..."
   mount $loopback $mountdir
   mv $mountdir/etc/rc.local.bak $mountdir/etc/rc.local
   umount $mountdir

From 0b19d6c6ea631ca2090610d601e7cddfd12f121a Mon Sep 17 00:00:00 2001
From: Andrew Scheller <github@loowis.durge.org>
Date: Mon, 22 Jan 2018 01:45:17 +0000
Subject: [PATCH 04/12] Add the -s flag to all parted commands

---
 pishrink.sh | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/pishrink.sh b/pishrink.sh
index 847caa9..936bf97 100755
--- a/pishrink.sh
+++ b/pishrink.sh
@@ -48,8 +48,8 @@ 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')
+partnum=$(parted -ms "$img" unit B print | tail -n 1 | cut -d ':' -f 1 | tr -d '\n')
+partstart=$(parted -ms "$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')
@@ -163,11 +163,11 @@ sleep 1
 losetup -d $loopback
 partnewsize=$(expr $minsize \* $blocksize | tr -d '\n')
 newpartend=$(expr $partstart + $partnewsize | tr -d '\n')
-parted "$img" rm $partnum >/dev/null
-parted "$img" unit B mkpart primary $partstart $newpartend >/dev/null
+parted -s "$img" rm $partnum >/dev/null
+parted -s "$img" unit B mkpart primary $partstart $newpartend >/dev/null
 
 #Truncate the file
-endresult=$(parted -m "$img" unit B print free | tail -1 | cut -d ':' -f 2 | tr -d 'B\n')
+endresult=$(parted -ms "$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)
 

From 49964b512c8e58f3518636e2ae0f86b9e7db7aad Mon Sep 17 00:00:00 2001
From: Andrew Scheller <github@loowis.durge.org>
Date: Mon, 22 Jan 2018 02:28:49 +0000
Subject: [PATCH 05/12] Remove the unnecessary `tr -d '\n'` parts

---
 pishrink.sh | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/pishrink.sh b/pishrink.sh
index 936bf97..b1a89ca 100755
--- a/pishrink.sh
+++ b/pishrink.sh
@@ -48,11 +48,11 @@ fi
 
 #Gather info
 beforesize=$(ls -lah "$img" | cut -d ' ' -f 5)
-partnum=$(parted -ms "$img" unit B print | tail -n 1 | cut -d ':' -f 1 | tr -d '\n')
-partstart=$(parted -ms "$img" unit B print | tail -n 1 | cut -d ':' -f 2 | tr -d 'B\n')
+partnum=$(parted -ms "$img" unit B print | tail -n 1 | cut -d ':' -f 1)
+partstart=$(parted -ms "$img" unit B print | tail -n 1 | cut -d ':' -f 2 | tr -d 'B')
 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 $loopback | grep 'Block size' | tr -d ' ' | cut -d ':' -f 2 | tr -d '\n')
+currentsize=$(tune2fs -l $loopback | grep 'Block count' | tr -d ' ' | cut -d ':' -f 2)
+blocksize=$(tune2fs -l $loopback | grep 'Block size' | tr -d ' ' | cut -d ':' -f 2)
 
 #Check if we should make pi expand rootfs on next boot
 if [ "$should_skip_autoexpand" = false ]; then
@@ -132,7 +132,7 @@ fi
 
 #Make sure filesystem is ok
 e2fsck -p -f $loopback
-minsize=$(resize2fs -P $loopback | cut -d ':' -f 2 | tr -d ' ' | tr -d '\n')
+minsize=$(resize2fs -P $loopback | cut -d ':' -f 2 | tr -d ' ')
 if [[ $currentsize -eq $minsize ]]; then
   echo "ERROR: Image already shrunk to smallest size"
   exit -6
@@ -140,11 +140,11 @@ fi
 
 #Add some free space to the end of the filesystem
 if [[ $(expr $currentsize - $minsize - 5000) -gt 0 ]]; then
-  minsize=$(expr $minsize + 5000 | tr -d '\n')
+  minsize=$(expr $minsize + 5000)
 elif [[ $(expr $currentsize - $minsize - 1000) -gt 0 ]]; then
-  minsize=$(expr $minsize + 1000 | tr -d '\n')
+  minsize=$(expr $minsize + 1000)
 elif [[ $(expr $currentsize - $minsize - 100) -gt 0 ]]; then
-  minsize=$(expr $minsize + 100 | tr -d '\n')
+  minsize=$(expr $minsize + 100)
 fi
 
 #Shrink filesystem
@@ -161,13 +161,13 @@ sleep 1
 
 #Shrink partition
 losetup -d $loopback
-partnewsize=$(expr $minsize \* $blocksize | tr -d '\n')
-newpartend=$(expr $partstart + $partnewsize | tr -d '\n')
+partnewsize=$(expr $minsize \* $blocksize)
+newpartend=$(expr $partstart + $partnewsize)
 parted -s "$img" rm $partnum >/dev/null
 parted -s "$img" unit B mkpart primary $partstart $newpartend >/dev/null
 
 #Truncate the file
-endresult=$(parted -ms "$img" unit B print free | tail -1 | cut -d ':' -f 2 | tr -d 'B\n')
+endresult=$(parted -ms "$img" unit B print free | tail -1 | cut -d ':' -f 2 | tr -d 'B')
 truncate -s $endresult "$img"
 aftersize=$(ls -lah "$img" | cut -d ' ' -f 5)
 

From 8784bda9899bbf2d8aba42c992630c154a2ce8a1 Mon Sep 17 00:00:00 2001
From: Andrew Scheller <github@loowis.durge.org>
Date: Mon, 22 Jan 2018 02:33:33 +0000
Subject: [PATCH 06/12] Avoid calling identical commands multiple times

---
 pishrink.sh | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/pishrink.sh b/pishrink.sh
index b1a89ca..188ce73 100755
--- a/pishrink.sh
+++ b/pishrink.sh
@@ -48,11 +48,13 @@ fi
 
 #Gather info
 beforesize=$(ls -lah "$img" | cut -d ' ' -f 5)
-partnum=$(parted -ms "$img" unit B print | tail -n 1 | cut -d ':' -f 1)
-partstart=$(parted -ms "$img" unit B print | tail -n 1 | cut -d ':' -f 2 | tr -d 'B')
+parted_output=$(parted -ms "$img" unit B print | tail -n 1)
+partnum=$(echo "$parted_output" | cut -d ':' -f 1)
+partstart=$(echo "$parted_output" | cut -d ':' -f 2 | tr -d 'B')
 loopback=$(losetup -f --show -o $partstart "$img")
-currentsize=$(tune2fs -l $loopback | grep 'Block count' | tr -d ' ' | cut -d ':' -f 2)
-blocksize=$(tune2fs -l $loopback | grep 'Block size' | tr -d ' ' | cut -d ':' -f 2)
+tune2fs_output=$(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)
 
 #Check if we should make pi expand rootfs on next boot
 if [ "$should_skip_autoexpand" = false ]; then

From c69f57affe066b480c985df526985f3d05c03908 Mon Sep 17 00:00:00 2001
From: Andrew Scheller <github@loowis.durge.org>
Date: Mon, 22 Jan 2018 02:34:58 +0000
Subject: [PATCH 07/12] Tighten up grep matches

---
 pishrink.sh | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/pishrink.sh b/pishrink.sh
index 188ce73..6cf98f0 100755
--- a/pishrink.sh
+++ b/pishrink.sh
@@ -53,8 +53,8 @@ partnum=$(echo "$parted_output" | cut -d ':' -f 1)
 partstart=$(echo "$parted_output" | cut -d ':' -f 2 | tr -d 'B')
 loopback=$(losetup -f --show -o $partstart "$img")
 tune2fs_output=$(tune2fs -l $loopback)
-currentsize=$(echo "$tune2fs_output" | grep 'Block count' | tr -d ' ' | cut -d ':' -f 2)
-blocksize=$(echo "$tune2fs_output" | grep 'Block size' | tr -d ' ' | cut -d ':' -f 2)
+currentsize=$(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)
 
 #Check if we should make pi expand rootfs on next boot
 if [ "$should_skip_autoexpand" = false ]; then

From ec95ba8097cdec13e3c0124b05e3de331b06ac15 Mon Sep 17 00:00:00 2001
From: Andrew Scheller <github@loowis.durge.org>
Date: Mon, 22 Jan 2018 02:39:33 +0000
Subject: [PATCH 08/12] `ls` doesn't need `-a` flag when passed a filename

---
 pishrink.sh | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/pishrink.sh b/pishrink.sh
index 6cf98f0..38d7266 100755
--- a/pishrink.sh
+++ b/pishrink.sh
@@ -47,7 +47,7 @@ if [ -n "$2" ]; then
 fi
 
 #Gather info
-beforesize=$(ls -lah "$img" | cut -d ' ' -f 5)
+beforesize=$(ls -lh "$img" | cut -d ' ' -f 5)
 parted_output=$(parted -ms "$img" unit B print | tail -n 1)
 partnum=$(echo "$parted_output" | cut -d ':' -f 1)
 partstart=$(echo "$parted_output" | cut -d ':' -f 2 | tr -d 'B')
@@ -171,6 +171,6 @@ parted -s "$img" unit B mkpart primary $partstart $newpartend >/dev/null
 #Truncate the file
 endresult=$(parted -ms "$img" unit B print free | tail -1 | cut -d ':' -f 2 | tr -d 'B')
 truncate -s $endresult "$img"
-aftersize=$(ls -lah "$img" | cut -d ' ' -f 5)
+aftersize=$(ls -lh "$img" | cut -d ' ' -f 5)
 
 echo "Shrunk $img from $beforesize to $aftersize"

From e3ff4d20aa68fc455b36fcd6352a7eebeb69f143 Mon Sep 17 00:00:00 2001
From: Andrew Scheller <github@loowis.durge.org>
Date: Mon, 22 Jan 2018 02:50:41 +0000
Subject: [PATCH 09/12] Double-quote all the filenames

---
 pishrink.sh | 30 +++++++++++++++---------------
 1 file changed, 15 insertions(+), 15 deletions(-)

diff --git a/pishrink.sh b/pishrink.sh
index 38d7266..8b45879 100755
--- a/pishrink.sh
+++ b/pishrink.sh
@@ -52,7 +52,7 @@ parted_output=$(parted -ms "$img" unit B print | tail -n 1)
 partnum=$(echo "$parted_output" | cut -d ':' -f 1)
 partstart=$(echo "$parted_output" | cut -d ':' -f 2 | tr -d 'B')
 loopback=$(losetup -f --show -o $partstart "$img")
-tune2fs_output=$(tune2fs -l $loopback)
+tune2fs_output=$(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)
 
@@ -60,13 +60,13 @@ blocksize=$(echo "$tune2fs_output" | grep '^Block size:' | tr -d ' ' | cut -d ':
 if [ "$should_skip_autoexpand" = false ]; then
   #Make pi expand rootfs on next boot
   mountdir=$(mktemp -d)
-  mount $loopback $mountdir
+  mount "$loopback" "$mountdir"
 
-  if [ $(md5sum $mountdir/etc/rc.local | cut -d ' ' -f 1) != "0542054e9ff2d2e0507ea1ffe7d4fc87" ]; then
+  if [ $(md5sum "$mountdir/etc/rc.local" | cut -d ' ' -f 1) != "0542054e9ff2d2e0507ea1ffe7d4fc87" ]; then
     echo "Creating new /etc/rc.local"
-    mv $mountdir/etc/rc.local $mountdir/etc/rc.local.bak
+    mv "$mountdir/etc/rc.local" "$mountdir/etc/rc.local.bak"
     #####Do not touch the following lines#####
-cat <<\EOF1 > $mountdir/etc/rc.local
+cat <<\EOF1 > "$mountdir/etc/rc.local"
 #!/bin/bash
 do_expand_rootfs() {
   ROOT_PART=$(mount | sed -n 's|^/dev/\(.*\) on / .*|\1|p')
@@ -125,16 +125,16 @@ rm -f /etc/rc.local; cp -f /etc/rc.local.bak /etc/rc.local; /etc/rc.local
 exit 0
 EOF1
     #####End no touch zone#####
-    chmod +x $mountdir/etc/rc.local
+    chmod +x "$mountdir/etc/rc.local"
   fi
-  umount $mountdir
+  umount "$mountdir"
 else
   echo "Skipping autoexpanding process..."
 fi
 
 #Make sure filesystem is ok
-e2fsck -p -f $loopback
-minsize=$(resize2fs -P $loopback | cut -d ':' -f 2 | tr -d ' ')
+e2fsck -p -f "$loopback"
+minsize=$(resize2fs -P "$loopback" | cut -d ':' -f 2 | tr -d ' ')
 if [[ $currentsize -eq $minsize ]]; then
   echo "ERROR: Image already shrunk to smallest size"
   exit -6
@@ -150,19 +150,19 @@ elif [[ $(expr $currentsize - $minsize - 100) -gt 0 ]]; then
 fi
 
 #Shrink filesystem
-resize2fs -p $loopback $minsize
+resize2fs -p "$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 $loopback
+  mount "$loopback" "$mountdir"
+  mv "$mountdir/etc/rc.local.bak" "$mountdir/etc/rc.local"
+  umount "$mountdir"
+  losetup -d "$loopback"
   exit -7
 fi
 sleep 1
 
 #Shrink partition
-losetup -d $loopback
+losetup -d "$loopback"
 partnewsize=$(expr $minsize \* $blocksize)
 newpartend=$(expr $partstart + $partnewsize)
 parted -s "$img" rm $partnum >/dev/null

From 8331faf8f3c0705975d205c76fbb91c0f9887f32 Mon Sep 17 00:00:00 2001
From: Andrew Scheller <github@loowis.durge.org>
Date: Mon, 22 Jan 2018 03:05:31 +0000
Subject: [PATCH 10/12] Check for additional required commands

---
 pishrink.sh | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/pishrink.sh b/pishrink.sh
index 8b45879..0f63f18 100755
--- a/pishrink.sh
+++ b/pishrink.sh
@@ -29,11 +29,13 @@ if (( EUID != 0 )); then
 fi
 
 #Check that what we need is installed
-which parted 2>&1 >/dev/null
-if (( $? != 0 )); then
-  echo "ERROR: parted is not installed."
-  exit -4
-fi
+for command in parted losetup tune2fs md5sum 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

From 201db16c933b6a1e6e5dd69aae3bc1c9986e3529 Mon Sep 17 00:00:00 2001
From: Andrew Scheller <github@loowis.durge.org>
Date: Mon, 22 Jan 2018 03:31:19 +0000
Subject: [PATCH 11/12] Replace `expr` with bash built-in arithmetic, and tidy
 up free-space calculation

---
 pishrink.sh | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/pishrink.sh b/pishrink.sh
index 0f63f18..aebc4ee 100755
--- a/pishrink.sh
+++ b/pishrink.sh
@@ -143,13 +143,13 @@ if [[ $currentsize -eq $minsize ]]; then
 fi
 
 #Add some free space to the end of the filesystem
-if [[ $(expr $currentsize - $minsize - 5000) -gt 0 ]]; then
-  minsize=$(expr $minsize + 5000)
-elif [[ $(expr $currentsize - $minsize - 1000) -gt 0 ]]; then
-  minsize=$(expr $minsize + 1000)
-elif [[ $(expr $currentsize - $minsize - 100) -gt 0 ]]; then
-  minsize=$(expr $minsize + 100)
-fi
+extra_space=$(($currentsize - $minsize))
+for space in 5000 1000 100; do
+  if [[ $extra_space -gt $space ]]; then
+    minsize=$(($minsize + $space))
+    break
+  fi
+done
 
 #Shrink filesystem
 resize2fs -p "$loopback" $minsize
@@ -165,8 +165,8 @@ sleep 1
 
 #Shrink partition
 losetup -d "$loopback"
-partnewsize=$(expr $minsize \* $blocksize)
-newpartend=$(expr $partstart + $partnewsize)
+partnewsize=$(($minsize * $blocksize))
+newpartend=$(($partstart + $partnewsize))
 parted -s "$img" rm $partnum >/dev/null
 parted -s "$img" unit B mkpart primary $partstart $newpartend >/dev/null
 

From 3568798dd45d6f2f03b90e821330fe98f2d831f8 Mon Sep 17 00:00:00 2001
From: Andrew Scheller <github@loowis.durge.org>
Date: Mon, 22 Jan 2018 03:41:45 +0000
Subject: [PATCH 12/12] Give the new file the same ownership as the old file
 (instead of having it always owned just by root)

---
 pishrink.sh | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/pishrink.sh b/pishrink.sh
index aebc4ee..cc5a671 100755
--- a/pishrink.sh
+++ b/pishrink.sh
@@ -45,6 +45,8 @@ if [ -n "$2" ]; then
     echo "ERROR: Could not copy file..."
     exit -5
   fi
+  old_owner=$(stat -c %u:%g "$1")
+  chown $old_owner "$2"
   img="$2"
 fi