Installing the insync or insync-headless package will add the repository entry automatically. These steps are kept for reference in case of issues.

APT (show)

1. First, add our public GPG key to allow apt to authenticate the Insync repository:
   

   sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys ACCAF35C

2. Create a file /etc/apt/sources.list.d/insync.listand add deb http://apt.insynchq.com/[DISTRIBUTION] [CODENAME] non-free contrib
   Replace [DISTRIBUTION] with your Linux distro: ubuntu, debian, mint
   Replace [CODENAME] with your Linux distro codename: for example Ubuntu 12.04 is precise
   (Source packages are not available, only binaries.)
3. Update the apt repository:
   

   $ sudo apt-get update

4. Install Insync
   

   $ sudo apt-get install insync

   File manager integration will be added when Insync is run.

The APT repository officially supports Debian, Mint, and Ubuntu only.
For other Debian-based distributions, try using the one for Debian Squeeze.

YUM (show)

1. First, import the public GPG key used to sign the RPMs.

   $ sudo rpm --import https://d2t3ff60b2tol4.cloudfront.net/repomd.xml.key

2. Create a new file insync.repo in /etc/yum.repos.d/ with the following content.

   [insync]
   name=insync repo
   baseurl=http://yum.insynchq.com/fedora/$releasever/
   gpgcheck=1
   gpgkey=https://d2t3ff60b2tol4.cloudfront.net/repomd.xml.key
   enabled=1
   metadata_expire=120m

3. Install Insync
   

   $ sudo yum install insync

   File manager integration will be added when Insync is run.