Image optimization bash script

Prerequisite

• jpegoptim for jpg optimization
• optipng for png optimization
• cwebp for WebP conversion

Debian/Ubuntu :

sudo apt install jpegoptim optipng webp -y

Centos 7 :

sudo yum install optipng jpegoptim libwebp-tools -y

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Installation

1. Clone the repository

git clone https://github.com/VirtuBox/img-optimize.git $HOME/.img-optimize

2. Install the script

Method 1 : Add an alias in .bashrc

With this method img-optimize can only be used by the current user

echo "alias img-optimize=$HOME/.img-optimize/optimize.sh" >> $HOME/.bashrc
source $HOME/.bashrc

Method 2 : Copy the script in /usr/local/bin

With this method img-optimize can be used by all users

sudo cp $HOME/.img-optimize/optimize.sh /usr/local/bin/img-optimize

Usage

Bash script to optimize your images and convert them in WebP
Usage: img-optimize [options] <images path>
If images path isn't defined, img-optimize will use the current directory
  Options:
       --jpg <images path> ..... optimize all jpg images
       --png <images path> ..... optimize all png images
       --webp <images path> ..... convert all images in webp
       --nowebp <images path> ..... optimize all png & jpg images
       --all <images path> ..... optimize all images (png + jpg + webp)
       -i, --interactive ..... run img-optimize in interactive mode
       -q, --quiet ..... run image optimization quietly
 Other options :
       -h, --help, help ... displays this help information
Examples:
  optimize all jpg images in /var/www/images
    img-optimize --jpg /var/www/images

Update the script

To update the script, just run :

git -C $HOME/.img-optimize pull

If you previously used the 2nd install method, you have to copy the script again to update it

sudo cp $HOME/.img-optimize/optimize.sh /usr/local/bin/img-optimize -f

Setup daily cronjob

You copy the scripts to /etc/cron.daily :

cp $HOME/.img-optimize/crons/jpg-png-cron.sh /etc/cron.daily/jpg-png-cron
cp $HOME/.img-optimize/crons/jpg-png-cron.sh /etc/cron.daily/webp-cron

chmod +x /etc/cron.daily/jpg-png-cron
chmod +x /etc/cron.daily/webp-cron

Then just edit your websites path set with the variables sites at the beginning of the cron scripts.

Warning

Conversion process can take a while, you can use tmux to launch the script and be able to close your ssh connection without interrupting conversion. Then just use tmux attach to login back in your tmux session.

Credits

• WebP conversion script was inspired by this DigitalOcean Community Tutorial

• Tutorial about webp conversion available on jesuisadmin.fr (in french)