How can we access the below C-Style CLI commands through RESTCONF interface?
file show
file list
Not possible. Those commands are built into the CLI agent only. For RESTCONF, I believe you will have to implement your own action to do that.
With NETCONF through RFC 6022 you can access files. Search for /confdConfig/netconf/capabilities/url in the UG and URL Capability examples - #2 by cohult