Add a timestamp watermark to photos

jpg_add_timestamp.sh

#!/bin/bash
# Change the font variable to point to your font location

#ok
font="/usr/share/fonts/truetype/lato/Lato-Thin.ttf"
#font="/home/amir/.local/share/fonts/Roboto-Light.ttf"

if [ $# -eq 0 ]
   then
      cat << _EOF_

USAGE: $0 file1 file2 ..., or
       $0 *.jpg, or
       $0 dir/*.jpg
       ...

_EOF_
      exit
fi

while [ "$1" != "" ]; do
        # Skip directories
        if [ -d "$1" ]; then
                shift
                continue
        fi
        # Skip already converted files (may get overwritten)
        if [[ $1 =~ ^.*DT.??? ]]
	then
              #  echo "------  Skipping: $1"
                shift
                continue
        fi

        # Work out a new file name by adding "_DT" before file extension
        file=$1
        echo "######  Working on file: $file"
        filename=${file%.*}
        extension=${file##*.}
#        output=${filename}_DT.${extension}
        output=${filename}_DT.png

        # Get the file dimension
        dim=$(identify -format "%w %h" "$file")
        width=${dim%% *}
        height=${dim#* }

        # Decide the font size automatically
        if [ $width -ge $height ]
        then
                pointsize=$(($width/60))
        else
                pointsize=$(($height/60))
        fi

    #    echo "        Width: $width, Height: $height. Using pointsize: $pointsize"


#au: changing the date format
printed_date=`exiftool -DateTimeOriginal "$file" | sed -r 's#.*20([0-9]{2}):([0-9]{2}):([0-9]{2}).*#\2/\1#'`
#remove leading 0, if any
printed_date2=`echo $printed_date | sed 's/^0*//'`


#to date: 
# date --date=`exiftool -DateTimeOriginal "AU(20120823_140042).JPG" | sed -r 's#.*([0-9]{4}):([0-9]{2}):([0-9]{2}).*#\1-\2-\3#'` 
####works, but not used:
#bday=`date --date "20090823"`
#picdate=`date --date=\`exiftool -DateTimeOriginal "$file" | sed -r 's#.*([0-9]{4}):([0-9]{2}):([0-9]{2}).*#\1-\2-\3#'\``
#age=$(( ( $(date -d "$picdate" +'%s') - $(date  -d "$bday" +'%s') )/60/60/24/365 ))
#agem=$(( ( $(date -d "$picdate" +'%s') - $(date  -d "$bday" +'%s') )/60/60/24/30 - 12*$age ))
#printed_date2=`echo ${printed_date},   ${age}y${agem}m | sed 's/^0*//'`
#### << works

        # The real deal here
    convert "$file" -gravity SouthEast -font "$font" -pointsize $pointsize -fill white -annotate +$pointsize+$pointsize "$printed_date2" "$output"

	#exifftool 

        shift
done

exit 0