Processing images using ImageMagick through bash scripts - bash

Question

I have a folder of images. I want to iterate through the folder, apply the same ImageMagick convert function to each file, and save the output to a separate folder.
The way I'm doing it currently is this:
#!/bin/bash
mkdir "Folder2"
for f in Folder1/*.png
do
echo "convert -brightness-contrast 10x60" "Folder1/$f" "Folder2/"${f%.*}"_suffix.png"
done
Then I copy and paste that terminal output into a new bash script that ends up looking like this:
#!/bin/bash
convert -brightness-contrast 10x60 Folder1/file1.png Folder2/file1_suffix.png
convert -brightness-contrast 10x60 Folder1/file2.png Folder2/file2_suffix.png
convert -brightness-contrast 10x60 Folder1/file3.png Folder2/file3_suffix.png
I tried to write a single bash script for this task but there was some weirdness with the variable handling, and this two-script method got me what I needed ...but I suspect there's an easier/simpler way and possibly even a one-line solution.

Answer 1

It's enough to change your first script, not to just echo the commands, but to execute them.
#!/bin/bash
mkdir "Folder2"
for f in Folder1/*.png
do
convert -brightness-contrast 10x60 "Folder1/$f" "Folder2/${f%.*}_suffix.png"
done

Answer 2

Crystal ball is telling me that there are spaces in filenames causing "some weirdness with the variable handling". In that case you need a workaround for the spaces. For example, you may try the following script:
#!/bin/bash
hasspaces="^(.+[^\'\"])([ ])(.+)$"
function escapespaces {
declare -n name=$1
while [[ $name =~ $hasspaces ]] ; do
name=${BASH_REMATCH[1]}'\'${BASH_REMATCH[2]}${BASH_REMATCH[3]}
echo 'Escaped string: '\'$name\'
done
}
mkdir Folder2
while read -r entry; do
echo "File '$entry'"
escapespaces entry
echo "File '$entry'"
tmp=${entry#Folder1}
eval "convert -brightness-contrast 10x60" "$entry" "Folder2/"${tmp%.*}"_suffix.png"
done <<<"$(eval "ls -1 Folder1/*.png")"
If this does not work, by all means let me know so I can request a refund for my crystal ball! Also, if you can give more details on the "weirdness in variable handling", we could try to help with those other weirdnesses :-)

Answer 3

Check this answer (and the few in the question) out:
You can use it in your example :
find Folder1 -name "*.png" | sed -e 'p;s/Folder1/Folder2/g' -e 's/.png/_suffix.png' | xargs -n2 convert -brightness-contrast 10x60
note : the p in the first sed makes the trick.
find will list you all the files in Folder1 with a name that matches the *.png expression
sed -e 'p;/Folder1/Folder2/g' will (a) print the input line and (b) replace Folder1 by Folder2
-e 's/.png$/_suffix.png' replaces the .png suffix with the _suffix.png suffix
xargs -n2 tells the shell that xargs should take two arguments max (the first one being printed by sed 'p' and the second one going through all the -e)
convert ... is your command, taking two inputs.