Parallel version of GDAL's nearblack tool for stripping black/white borders from images.

nearblack-parallel.sh

#!/bin/bash

USAGE="Runs GDAL nearblack utility over files in a directory tree in parallel.

Usage: $0 SOURCE/ DEST/ [nearblack options]

Recommended/default nearblack options: 
  -setalpha -white -nb 0 -near 0  -of GTiff -co COMPRESS=DEFLATE -co TILED=YES

See more details on nearblack at: http://www.gdal.org/nearblack.html

Requires GNU Parallel & GDAL >= 1.8. Get Parallel .deb files from:
https://build.opensuse.org/package/show?package=parallel&project=home:tange"

if [ "$#" -lt "2" ]; then
	echo "$USAGE"
	exit 2
fi

SOURCEPATH=$1
shift
DESTPATH=$1
shift

if [ "$#" == "0" ]; then
	NBARGS="-setalpha -white -nb 0 -near 0 -of GTiff -co TILED=YES -co COMPRESS=DEFLATE"
else
	NBARGS="$@"
fi

find "$SOURCEPATH" -type f "(" -iname "*.JPG" -o -iname "*.TIF" -o -iname "*.TIFF" ")" -printf "%P\0" | \
	parallel -0 --eta -u \
	"mkdir -p \"$DESTPATH/{//}\"; nearblack -q -o \"$DESTPATH/{}\" $NBARGS \"$SOURCEPATH{}\""