I have worked in the computer industry as a network & systems admin for 18 years. Building mostly Windows or Linux servers & workstations. I have also contracted to install and upgrade POS systems.
In case it's not clear, tree is not a shell built-in, it's the name of an external program (e.g. /usr/bin/tree.) Therefore it doesn't matter what shell you're using; either the program is installed or it isn't. Apt-get install tree, or brew install tree, or whatever other tool you use to install apps use that to install tree. ;)
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In case it's not clear, tree is not a shell built-in, it's the name of an external program (e.g. /usr/bin/tree.) Therefore it doesn't matter what shell you're using; either the program is installed or it isn't. Apt-get install tree, or brew install tree, or whatever other tool you use to install apps use that to install tree. ;)