The standard CTRL-E works to go to the end of the line but CTRL-A doesn't seem to work to go to the beginnig.
It would obviously be useful to quickly go to the beginning of line for example if one wanted to replace w /path/to/file in with w! /path/to/file.
Is there a key to go to the beginning of the line in command mode and if so how does one map it to CTRL-A?