While playing around with Intel Edison there is a chance that you brick it. There are number of issues you might encounter.
1) Not being able to view edison as a external hard drive.
2) Some of the commands not working.
You can try flashing the edison again. There are multiple ways of doing this.
1) For linux users - https://software.intel.com/en-us/flashing-firmware-with-flash-tool-lite
2) For MAC users - http://www.intel.com/support/edison/sb/CS-035262.htm
3) For Windows users - http://www.intel.com/support/edison/sb/CS-035286.htm
Second method is to use Phone Flashtool - https://software.intel.com/en-us/articles/flash-tool-lite-user-manual
Additional Notes & Troubleshooting:Note: You can also flash the Intel Edison with the debian image for the Edison.
Note : Only applies to Macbook users.
"While trying to re install firmware I encountered this issue. My Macbook wasn't detecting the Edison as a usb drive. I tried the first method, it did not work for me. But when I tried the second method it worked out well. However the drive was completely formatted. It showed up as Gadget Media on my disk utility( You can find disk utility by pressing command + space ). So I used Step 3.2 from the first method. http://www.intel.com/support/edison/sb/CS-035262.htm.
After doing that I did all the steps after step 3.2 in the same link."