Suggestion: Default to create file_shrunk.img from file.img if no argument passed

[J-o-h-n-U]

Just a minor suggestion, a mod I've made to my local copy of the script to fit my needs / laziness.

If no output file is specified, use input_shrunk.img

I also modified it so that if I've run the script unsuccessfully for whatever reason and the destination already exists, save a lengthy copy procedure by just operating on the existing output file - this is likely NOT what most people want but is included here as it would be easy to put a "re-use destination y/n?" switch in there.

if [ -n "$2" ]; then
	f="$2"
  if [[ -n $ziptool && "${f##*.}" == "${ZIPEXTENSIONS[$ziptool]}" ]]; then	# remove zip extension if zip requested because zip tool will complain about extension
    f="${f%.*}"
  fi
else
  #echo "$img -> ${img%.img}_shrunk.img"
  f="${img%.img}_shrunk.img"
  echo "No output specififed, using $f"
fi

# Check existence of file - we don't care but others might
if [ -f $f ];then
	# Could put a yes/no check in here for safety
	echo "$f exists, assuming this is OK to use"
else
	info "Copying $1 to $f..."
	cp --reflink=auto --sparse=always "$1" "$f"
	if (( $? != 0 )); then
	error $LINENO "Could not copy file..."
	exit 5
	fi
fi

[Drewsif]

Thank you for the suggestion! I think the default behavior of having it shrink the image in place is my preference. But if enough people chime in I'm open to the change!

For the 2nd bit, I anticipate more issues with partially edited images that I would rather not have crop up. So the current copy anyway feels a bit safer. What errors were you running into that re-running fixed?

[J-o-h-n-U]

On the 1st one, there could perhaps be a warning about over-writing the original with a y/n choice input to either overwrite or create a "_shrunk" copy.

On the 2nd bit it's so long since I ran into it that I'm afraid I can't remember the exact problem, for my sins I believe it was related to running it from a Linux VM on a Windows host for various complicated reasons that are my problem not yours. I don't know if there's any way to quickly verify the extant copy is valid or not.