How to test for possible conflicts while using alias in bashrc?

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http://unix.stackexchange.com – Is there a simple way to list all the command conflicts that have occurred in the system due to the bashrc update involving alias commands? For example, someone writes alias ls=/path/to/user-generated/executable in bashrc. How does one find out that this is masking an actual command (ls). One way seems to be to run all the aliases before and after sourcing bashrc and diff the output. Are there any better ways? I'm running Ununtu 12.04. (HowTos)