Optimize shell acquisition order

[shanjunmei]

reverse_ssh/internal/client/handlers/shell.go

Line 24 in 581c6c5

var potentialShells []string

Here, if the shell list is read from the system configuration file(/etc/shells), when the client connection come in, take it in reverse order. If it is guessed, take the first one in order, and the experience will be better, because it seems that the list in front of the system configuration is generally It's all sh, a bit too ugly. . ?

[NHAS]

Hey, this is a good idea.
However, I am a little worried that if I reverse shells we'll end up with a non-standard shell like git shell, (or screen).

It might be better to rethink the search entirely and use shells as an indicator of known good shells, rather than as a definitive list of shells.

Regardless. I agree that the default of sh is a pain

[NHAS]

This has now been fixed/updated, a list of good shells will be searched for by default. Failing to find any of those good shells in PATH they will be looked up in the /etc/shells if that files, then a bruteforce will be carried out in common executable containing directories.

	goodShells = []string{
		"zsh",
		"bash",
		"fish",
		"dash",
		"ash",
		"csh",
		"ksh",
		"tcsh",
		"sh",
	}

List of common good shells that will be searched for (note the order, sh last).

This issue will be considered closed when you give confirmation that this fixes what you were experiencing, or when I merge this into master (as I've tested it myself)

[shanjunmei]

tested ,work fine