add support to resize and create image from trcard

pishrink.sh

@@ -161,7 +161,7 @@ EOF1
 help() {
 	local help
 	read -r -d '' help << EOM
-Usage: $0 [-adhrsvzZ] imagefile.img [newimagefile.img]
+Usage: $0 [-adhrsvzZn] imagefile.img [newimagefile.img]
 
   -s         Don't expand filesystem when image is booted the first time
   -v         Be verbose
@@ -170,6 +170,7 @@ Usage: $0 [-adhrsvzZ] imagefile.img [newimagefile.img]
   -Z         Compress image after shrinking with xz
   -a         Compress image in parallel using multiple cores
   -d         Write debug messages in a debug log file
+  -n         Accept an input that is not a file (e.g. a tf card)
 EOM
 	echo "$help"
 	exit 1
@@ -181,8 +182,9 @@ repair=false
 parallel=false
 verbose=false
 ziptool=""
+notfile=false
 
-while getopts ":adhrsvzZ" opt; do
+while getopts ":adhrsvzZn" opt; do
   case "${opt}" in
     a) parallel=true;;
     d) debug=true;;
@@ -192,6 +194,7 @@ while getopts ":adhrsvzZ" opt; do
     v) verbose=true;;
     z) ziptool="gzip";;
     Z) ziptool="xz";;
+    n) notfile=true;;
     *) help;;
   esac
 done
@@ -215,10 +218,14 @@ if [[ -z "$img" ]]; then
   help
 fi
 
+if [ "$notfile" = false ]; then
+  echo "$notfile"
   if [[ ! -f "$img" ]]; then
     error $LINENO "$img is not a file..."
     exit 2
   fi
+fi
+
 if (( EUID != 0 )); then
   error $LINENO "You need to be running as root."
   exit 3
@@ -257,6 +264,7 @@ done
 
 #Copy to new file if requested
 if [ -n "$2" ]; then
+  if [ "$notfile" = false ]; then #Skip copy if input is device
     f="$2"
     if [[ -n $ziptool && "${f##*.}" == "${ZIPEXTENSIONS[$ziptool]}" ]]; then	# remove zip extension if zip requested because zip tool will complain about extension
       f="${f%.*}"
@@ -271,6 +279,7 @@ if [ -n "$2" ]; then
     chown "$old_owner" "$f"
     img="$f"
   fi  
+fi
 
 # cleanup at script exit
 trap cleanup EXIT
@@ -292,7 +301,11 @@ if [ -z "$(parted -s "$img" unit B print | grep "$partstart" | grep logical)" ];
 else
   parttype="logical"
 fi
+if [ "$notfile" = false ]; then
   loopback="$(losetup -f --show -o "$partstart" "$img")"
+else
+  loopback=""$img""2""
+fi
 tune2fs_output="$(tune2fs -l "$loopback")"
 rc=$?
 if (( $rc )); then
@@ -374,6 +387,7 @@ if (( $rc )); then
 fi
 
 #Truncate the file
+if [ "$notfile" = false ]; then 
   info "Shrinking image"
   endresult=$(parted -ms "$img" unit B print free)
   rc=$?
@@ -390,6 +404,20 @@ if (( $rc )); then
     error $LINENO "trunate failed with rc $rc"
     exit 16
   fi
+else #Skip truncate if input is device
+  if [ -n "$2" ]; then
+    target="$2"
+    info "Creating image"
+    fdiskresult=$(fdisk -l "$img")
+    count=$(tail -1 <<< "$fdiskresult" | tr -s ' ' | cut -d ' ' -f 3)
+    bs=$(head -3 <<< "$fdiskresult" | tail -1 | tr -s ' ' | rev | cut -d ' ' -f 2 | rev)
+    dd if="$img" of="$target" bs="$bs" count="$count"
+    img="$target"
+  else
+    info "File system shrinked from $beforesize to $aftersize, no image created"
+    exit 0
+  fi
+fi
 
 # handle compression
 if [[ -n $ziptool ]]; then