APT

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. Edit /etc/apt/sources.list and 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

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
   repo_gpgcheck=1
   metadata_expire=120m

3. Install Insync
   

   $ sudo yum install insync

   File manager integration will be added when Insync is run.