Hello Ricarte,
Not sure I follow your question but let me explain something:
can i copy running-config to another file in the flash, do testing on it, if something goes wrong, put it back. like...
asa>copy running-config my-config
Yes, it is possible
copy my-config running-config
This will do a merge of both the file my-config and the running-config.. It will be a merge.
A merge adds any new commands from the new configuration to the running configuration. If the configurations are the same, no changes occur. If commands conflict or if commands affect the running of the context, then the effect of the merge depends on the command. You might get errors, or you might have unexpected results.
Julio Carvajal
Senior Network Security and Core Specialist
CCIE #42930, 2xCCNP, JNCIP-SEC