Doc (usually run as go doc) accepts zero, one or two arguments. Zero arguments: Show the documentation for the package in the current directory. One argument: The first item in this list that succeeds is the one whose documentation is printed. If there is a symbol but no package, the package in the current directory is chosen. However, if the argument begins with a capital letter it is always assumed to be a symbol in the current directory. Two arguments: Show the documentation for the package, symbol, and method or field. The first argument must be a full package path. This is similar to the command-line usage for the godoc command. For commands, unless the -cmd flag is present "go doc command" shows only the package-level docs for the package. The -src flag causes doc to print the full source code for the symbol, such as the body of a struct, function or method. The -all flag causes doc to print all documentation for the package and all its visible symbols. The argument must identify a package. For complete documentation, run "go help doc".