====== Convert to JPG =====

<code bash>mogrify -format jpg *.bmp</code>


====== Convert images to PDF =====
<code bash>convert pages_*.png final.pdf</code>
<code bash>convert pages_*.png -resize 50% -compress jpeg -quality 75 final.pdf</code>


====== merge PDFs ======
<code bash>pdfunite in-1.pdf in-2.pdf in-n.pdf out.pdf</code>

====== Process PDF pages ======
<code bash>
convert -density 300 scanned.pdf output-%02d.png

convert output*.png -normalize -threshold 80% normal.png
# or
convert output*.png +dither -colors 2 -colorspace Gray -normalize normal.png
# or
convert output*.png -monochrome normal.png # <-- this product nice dithered B&Wimage

convert normal*.png final.pdf
</code>

One liner:
<code bash>
convert -density 300 scanned.pdf -monochrome output.pdf
convert -density 300 scanned.pdf -normalize -threshold 70% output.pdf
</code>

====== Rename images to EXIF date ======

Use **krename** application.

===== jhead =====
<code bash>
jhead -n%Y%m%d-%H%M%S *.jpg 
</code>

===== exiv2 =====
exiv2 -k -r '%Y-%m-%d_%H-%M-%S_:basename:' rename "$i"
exiv2 -v -r '%Y%m%d.%H%M%S.:basename:' rename "$i"

===== exiftool =====
<code bash>
exiftool -d %Y-%m-%d_%H-%M-%S%%-c.%%e "-filename<CreateDate" DIR 
If you want to keep track of original filename and write extension lower case:

exiftool -d %Y%m%d_%H%M%S%%-c-%%f.%%le "-filename<DateTimeOriginal" [.|DIR]
The same works also with the whole filename in lowercase:

exiftool -d %Y%m%d_%H%M%S%%-c-%%lf.%%le "-filename<DateTimeOriginal" [.|DIR]
</code>


====== Remove EXIF data ======
<code bash>
for i in *.jpg; do echo "Processing $i"; exiftool -all= "$i"; done
</code>