nix --help: Show usage examples

This commit is contained in:
Eelco Dolstra 2016-04-21 14:58:32 +02:00
parent 1b0088ebb2
commit 69e3ffb076
3 changed files with 41 additions and 0 deletions

View file

@ -5,6 +5,21 @@ namespace nix {
Commands * RegisterCommand::commands = 0;
void Command::printHelp(const string & programName, std::ostream & out)
{
Args::printHelp(programName, out);
auto exs = examples();
if (!exs.empty()) {
out << "\n";
out << "Examples:\n";
for (auto & ex : exs)
out << "\n"
<< " " << ex.description << "\n" // FIXME: wrap
<< " $ " << ex.command << "\n";
}
}
MultiCommand::MultiCommand(const Commands & _commands)
: commands(_commands)
{

View file

@ -11,6 +11,18 @@ struct Command : virtual Args
virtual std::string name() = 0;
virtual void prepare() { };
virtual void run() = 0;
struct Example
{
std::string description;
std::string command;
};
typedef std::list<Example> Examples;
virtual Examples examples() { return Examples(); }
void printHelp(const string & programName, std::ostream & out) override;
};
class Store;

View file

@ -36,6 +36,20 @@ struct CmdVerify : StorePathsCommand
return "verify the integrity of store paths";
}
Examples examples() override
{
return {
Example{
"To verify the entire Nix store:",
"nix verify --all"
},
Example{
"To check whether each path in the closure of Firefox has at least 2 signatures:",
"nix verify -r -n2 --no-contents $(type -p firefox)"
},
};
}
void run(ref<Store> store, Paths storePaths) override
{
restoreAffinity(); // FIXME