Stephans Blog

My bash shell scripting has gotten very rusty lately (and ugly), but it’s still good enough to have some fun. For my photo site I need a short program which creates a description string like "Shot with Canon PowerShot S3 IS at 63.9 mm (383.4 mm), 1/320 s, 100, Matrix, F3.5, Auto" from an image. Some shell scripting later I was done.

#!/bin/bash

DIR=$1
rm -rf $DIR/exif
mkdir $DIR/exif

for file in $DIR/*.JPG
do
file=`basename ${file}`
filename=${file/.JPG/}
output=${filename}_EXIF.txt
exiv2 $DIR/$file | awk '
 BEGIN{FS=":"}
 /model/{ model=$2}
 /Focal length/{focal=$2}
 /Exposure time/{exposure=$2}
 /ISO/{iso=$2}
 /Metering/{metering=$2}
 /^Aperture/{aperture=$2}
 /White/{wb=$2}
 END{
   printf (
      "%s;%s;%s;%s;%s;%s;%s",
      model,focal,exposure,iso,metering,aperture,wb
   );
 }'
  | sed -e"s/\s\s*/ /g"
  | sed -e "s/^\s//g"
  | sed -e "s/;\s/;/g" > $DIR/exif/$output

IFS=";"
read model focal exposure iso metering aperture wb <<END
   $(cat $DIR/exif/$output)
END
multiplier=1
if [ $model == "Canon PowerShot S3 IS" ]; then
  multiplier=6
fi
focal_value=$(echo $focal | awk '{print $1}')
focal_equiv=$(echo "$focal_value * $multiplier" | bc -l)
echo "Shot with $model at $focal ($focal_equiv mm), $exposure, $iso, $metering, $aperture, $wb" > $DIR/exif/$output

 done