gitea-tea/vendor/github.com/kevinburke/ssh_config/README.md
Norwin d6df0a53b5 Update Dependencies (#390)
Co-authored-by: Norwin Roosen <git@nroo.de>
Co-authored-by: Norwin <git@nroo.de>
Reviewed-on: https://gitea.com/gitea/tea/pulls/390
Reviewed-by: 6543 <6543@obermui.de>
Reviewed-by: Andrew Thornton <art27@cantab.net>
Co-authored-by: Norwin <noerw@noreply.gitea.io>
Co-committed-by: Norwin <noerw@noreply.gitea.io>
2021-08-30 23:18:50 +08:00

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# ssh_config
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](https://golang.org/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.
```go
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.
```go
files := ssh_config.GetAll("myhost", "IdentityFile")
```
You can also load a config file and read values from it.
```go
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.
### Manipulating SSH config files
Here's how you can manipulate an SSH config file, and then write it back to
disk.
```go
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())
```
## Spec compliance
Wherever possible we try to implement the specification as documented in
the `ssh_config` manpage. Unimplemented features should be present in the
[issues][issues] list.
Notably, the `Match` directive is currently unsupported.
[issues]: https://github.com/kevinburke/ssh_config/issues
## Errata
This is the second [comment-preserving configuration parser][blog] I've written, after
[an /etc/hosts parser][hostsfile]. Eventually, I will write one for every Linux
file format.
[blog]: https://kev.inburke.com/kevin/more-comment-preserving-configuration-parsers/
[hostsfile]: https://github.com/kevinburke/hostsfile
## Donating
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
kev@inburke.com. Donations are not tax deductible in the USA.