Convert .png files to .jpg and compress them throughout many subdirectories

[tzell]

Hi forum,
I'm pretty new to bash.

I have multiple .png and large .jpg files throughout multiple sub directories

Trying to achieve the following:
1. Convert all .png files to .jpg files throughout all sub directories.
2. Optimize .jpg files for better compression (about 80% quality).
3. Delete all obselete .png files.

I found the following commands to:
1. convert png to jpg (with imagemagick)

Code: Select all

 mogrify -format jpg *.png 

2. Optimize jpg

Code: Select all

 jpegoptim *.jpg -m 80 

Reading online I saw there's ways to do similar file operations with find command, or bash scripting with for loop.
How do I accomplish this? Which way should I pick and how? Couldn't get it to work.

Thanks!

EDIT:
Turns out I had to add "+" at the end of the -exec command following "find".
So it works with the following code, when I run each line seperately:

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find -name *.png -exec mogrify -format jpg {} +

find -name *.jpg -exec jpegoptim -m 80 {} +

find -name *.png -exec rm {} +

Is this the way to do it? Or is there a better more elegant way?

[1000]

1. Put the files into the new folder ( if you can )
2. Test how this example working

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#!/bin/bash

PATH_to_png="/YOUR/PATH/TO/PNG_FILES"

for FILE_name in $(ls "$PATH_to_png") ; do
    echo "FILE_name = $FILE_name"
done 

echo " Finished."

3. Test your command in terminal.
4. Test your command instead "echo" command in example.

EDIT:
You can use "find" command but use more options to specify the files
for example find /your/path -type f

[tzell]

Thank you for your reply,
I already ran the command using the 'find' examples above
Yes admittedly I rushed it without testing too much (Before seeing your answer)

Hoping removing the .png file didn't remove more than it needed to using the find command

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find -name *.png -exec rm {} +

I didn't specify the -type

[1000]

Very often, we can accept a risk if we know that the command will not do anything more than it should.
For example, if we checked / tested first what the command "find" can found.

For "find" command " if no starting-point is specified, `.' ( ./ ) is assumed.
If we make a mistake and we execute the command elsewhere, it will find other files.

When I tested "find" command without quotation marks ( was file *.png and folder *.png )

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$ find  -name *.png
find: paths must precede expression: `jhgjh.png'
find: possible unquoted pattern after predicate `-name'?

So it's a nice security feature.