single click

[Aetheist]

How can I change double clock on single click in Gnome?

[hard candy]

I would suggest Google as it brought up this entry first when I searched your question:
Choose Double-Click or Single-Click




You can configure the mouse to activate files and applications with a double- or a single-click, whichever you prefer. Click on the icon for the Nautilus Start Here screen on the desktop (there is also one on the panel). This opens the file manager. Click on Preferences at the top of the screen and then select Edit Preferences. The preferences screen opens, showing a list of configurable options on the left. Click on Icon and List Views. Now make your selection for double or single mouse click in the top section of this window. Click on Ok and this change takes place immediately.