Slack is one of the most widely used communication software. Not just for companies but also for a lot of free and open source projects. One of the reason for Slack's big success is the support for multiple Operating Systems; Slack runs on macOS, Windows and Linux.
Download from Slack website
Usually one would download the relevant package from the Slack for Linux download page.
The download page offers a RPM and a DEB installation package. Once downloaded, the package can be installed. Either by using the command line (rpm or dpkg commands) or by double-click on the file in a desktop/GUI environment.
Installation from APT repository
For Debian and its derivatives (Ubuntu, Linux Mint and many more), Slack can also be installed from a public APT repository.
First download the package sign key:
ck@mint:~$ curl -fsSL https://packagecloud.io/slacktechnologies/slack/gpgkey | gpg --dearmor | sudo tee -a /etc/apt/keyrings/slacktechnologies_slack-archive-keyring.gpg
Then add the repository to the APT repos:
ck@mint:~$ echo "deb [signed-by=/etc/apt/keyrings/slacktechnologies_slack-archive-keyring.gpg] https://packagecloud.io/slacktechnologies/slack/debian jessie main" | sudo tee -a /etc/apt/sources.list.d/slack.list
Note that as of writing this article (January 2025), the "debian jessie" entry is used for all Debian, Ubuntu and other deb derivatives.
Update the apt repos:
ck@mint:~$ sudo apt update
Slack can now be installed using the "slack-desktop" package:
ck@mint:~$ sudo apt install slack-desktop