ubun2

I like to quickly see how much memory available, usage and free in ubuntu server. please help

The other day i was looking at a demo of a seo methodology online and the way they presented was pretty cool. So, i was caught into the way of mind mapping the ideas. I would appreciate if someone could point me to a free mind mapping software that is available free of cost and most preferebly open source. thanks for the help.

I am looking for a good free ubuntu backup software tool, please help.
 
Please suggest the best free open source and not commercial software you have used for quite some time and happy about it.
 
It would be great if the software has the following features

• Backup folders
• Restore folders
• Differential backup
• Scheduled backup and restore
• Backup while the machine is idle
• Support multiple hardware like USB, External Hard Drive, etc.,