Canonical checker

​For search, a header tag can be very important. We have many areas with duplicate pages, or at least very similar pages. That's bad news for ranking in external search engines as the 'rank equity', or 'ranking love' like some would say, is diluted.
For many situations this rel canonical tag can be used. It indicates to search engines, which of the many urls for the same content should rank in search results. It is one of the well understood and well working elements in seo.

Unfortunately though, some webpages don't make full use of this. Most tools, internally and externally, show if a canonical is on a page, but they don't check anything else, particularly not if the canonical is self-referring to the url of the page on which it is implemented.
These self-referring canonicals are nothing bad, even recommended, but if we have 3 urls for the same content (think segments or customer segments) all have a self referring canonical we need to change this to one having the self referring, and the other two refer to that url with the self-referring one.

Knowledge is the parent of action or so, right?

Here is a little tool to check in your area, works under linux and also on cygwin. Suggestions for improvement welcome as always.  

#bash
echo -e "\033[91m if url in feeding file had NO http or https, http is assumed and set \033[0m"
if ! [[ -f $1 ]]; then
echo "need a file with urls starting with http or https"
return
fi

echo -e "URL tested\tcanonical status"
while read line; do
if [[ ! $line == http* ]]; then
line="http://"$line
fi
response=$(curl -I -s --write-out %{http_code} "$line" -o /dev/null)
if [[ $response == 200 ]]; then
canonical=$( curl -s --max-time 3 "$line" | grep "canonical" | grep -o '<.*canonical.*>' | sed -e 's/<link //' -e 's/rel=//' -e 's/canonical//' -e 's/href=//' -e 's/ //g' -e 's/\x22//g' -e 's/\x27//g' -e 's/\/>$//' )
case $canonical in
*hreflang*)
canonical="coding error"
;;
"")
canonical="none"
;;
*/)
canonical="${canonical%/}"
;;
*)
canonical="${canonical}"
esac
if [[ $line == $canonical ]]; then
canonical="\033[32mmatch\033[0m"
fi
else canonical="redirected"
fi
echo -e "$line\t$canonical" | tee -a output.txt

done < $1

Reduce pictures with a script for imagemagick

Blogging is fun, but can be quite some effort. One of the things necessary is to scale pictures so they fit into the blog, are large and sharp enough to show the details necessary, but also be as small as possible to have great page load times.

The best results I can possibly generate are with photoshop, and that also has a nice batch option. On Windows Irfanview is a great tool to automate this super easily in pretty good quality as well. My tool of choice on linux is imagemagick. While it has tons of options, below setting works great for me.

This script I start from the folder with the pictures. It takes one parameter on call - the length wanted for the longer side. So, calling it like 'image-resize.sh 800'  is the way to go.
It would check if the folder exists and if not generate it; then rename all filenames in the startfolder to small letters, then rename .jpeg to .jpg to make all jpg accessible to the imagemagic script.

#!bash
if [[ ! -d $1 ]]
      then mkdir "$1"
fi 

rename 'y/A-Z/a-z/' *
rename 's/\.jpeg/\.jpg/' *

for i in *.jpg
convert "$i" -resize "${1}^>" -quality 25% -unsharp 1.2x1.2+1+0 "$1"/s_"$i"
done

Then it reduce pictures where the larger side (height or width) is larger than 800 px to exactly 800 px. It maintains the ratio, sharpens as well and reduces the quality to 30% as well - a value I found the sweet spot between quality and image size for many of my pictures. Final step is to add a s_ to the filename and generate it into that folder. Most important insight (from a forum) was the setting for 'value^>' - setting the longer side to this value.