This is a Go parser for ssh_config files. Importantly, this parser attempts to preserve comments in a given file, so you can manipulate a ssh_config file from a program, if your heart desires.

It's designed to be used with the excellent x/crypto/ssh package, which handles SSH negotiation but isn't very easy to configure.

The ssh_config Get() and GetStrict() functions will attempt to read values from $HOME/.ssh/config and fall back to /etc/ssh/ssh_config. The first argument is the host name to match on, and the second argument is the key you want to retrieve.

port := ssh_config.Get("myhost", "Port")

Certain directives can occur multiple times for a host (such as IdentityFile), so you should use the GetAll or GetAllStrict directive to retrieve those instead.

files := ssh_config.GetAll("myhost", "IdentityFile")

You can also load a config file and read values from it.

var config = `
Host *.test
  Compression yes
`

cfg, err := ssh_config.Decode(strings.NewReader(config))
fmt.Println(cfg.Get("example.test", "Port"))

Some SSH arguments have default values - for example, the default value for KeyboardAuthentication is "yes". If you call Get(), and no value for the given Host/keyword pair exists in the config, we'll return a default for the keyword if one exists.

Here's how you can manipulate an SSH config file, and then write it back to disk.

f, _ := os.Open(filepath.Join(os.Getenv("HOME"), ".ssh", "config"))
cfg, _ := ssh_config.Decode(f)
for _, host := range cfg.Hosts {
    fmt.Println("patterns:", host.Patterns)
    for _, node := range host.Nodes {
        // Manipulate the nodes as you see fit, or use a type switch to
        // distinguish between Empty, KV, and Include nodes.
        fmt.Println(node.String())
    }
}

// Print the config to stdout:
fmt.Println(cfg.String</