Mac Lion Prevent restart after a new software install or uninstall Sometimes, Mac requires a restart after installing or uninstalling an application. What are the steps to prevent complete restart cycle and still achieve the desired result?

I remember I used to do a soft restart in terminal but now forgot the steps. After soft restart, the "uptime" command in terminal used to continue from previous uptime value, like "up 20 days".
You can install updates without restarting by running sudo softwareupdate -i -a. It might cause some issues though. When I installed the 10.8.3 update without restarting, Safari started crashing on launch until I restarted the Mac.

If an installer or uninstaller forces you to restart, you can often just press command-Q to quit the installer.

I haven't heard of anything like a soft restart. You can quit all applications by running sudo killall loginwindow, but it doesn't have the same effect as restarting or logging out and back in.