From 57a69657c83e51da9e2f5a572533f430db6c637f Mon Sep 17 00:00:00 2001
From: Csaba Kiraly <csaba.kiraly@gmail.com>
Date: Thu, 24 Nov 2016 11:59:51 +0100
Subject: [PATCH] do not truncate if used directly on the SD

---
 pishrink.sh | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/pishrink.sh b/pishrink.sh
index f2df6b9..73b9b6e 100755
--- a/pishrink.sh
+++ b/pishrink.sh
@@ -150,8 +150,9 @@ 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"
+if [[ -f $img ]]; then
+  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"
+fi