Go parser for ssh_config files
This is a Go parser for
ssh_configfiles. Importantly, this parser attempts to preserve comments in a given file, so you can manipulate a
ssh_configfile 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/configand 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")
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
KeyboardAuthenticationis
"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())
Wherever possible we try to implement the specification as documented in the
ssh_configmanpage. Unimplemented features should be present in the issues list.
Notably, the
Matchdirective is currently unsupported.
This is the second comment-preserving configuration parser I've written, after an /etc/hosts parser. Eventually, I will write one for every Linux file format.
Donations free up time to make improvements to the library, and respond to bug reports. You can send donations via Paypal's "Send Money" feature to [email protected] Donations are not tax deductible in the USA.