Execute Command In Multiple Directories - linux

Question

I have a large set of single install WordPress sites on my Linux server. I want to create text files that contain directory names for groups of my sites.
For instance all my sites live in /var/www/vhosts and I may want to group a set of 100 websites in a text file such as
site1
site2
site3
site4
How can I write a script that will loop through only the directories specified in the group text files and execute a command. My goal is to symlink some of the WordPress plugins and I don't want to have to manually go directory by directory if I can just create groups and execute the command within that group of directories.
For each site in the group file, go to the /wp-content/plugins folder and execute the symlink command specified.

Answer 1

Depending on your goals, you may be able to achieve that with a one-liner using find and an -exec action. I tend to like doing it as a Bash loop, because it is easier to add additional commands instead of having a long and unwieldy command doing it all, as well as handle errors.
I do not know if this is what you intend, but here is a proposal.
#!/bin/bash
# Receives site group file as argument1
# Receives symlink name as argument 2
# Further arguments will be passed to the command called
sites_dir="/var/www/vhosts"
commands_dir="wp-content/plugins"
if ! [[ -f $1 ]] ; then
echo "Site list not found : $1"
exit
fi
while IFS= read -r site
do
site_dir="$sites_dir/$site"
if ! [[ -d $site_dir ]] ; then
echo "Unknown site : $site"
continue
fi
command="$site_dir/$commands_dir/$2"
if ! [[ -x $command ]] ; then
echo "Missing or non-executable command : $command"
continue
fi
"$command" "${#:3}"
done <"$1"