ssh tab completion with host name

[protist]

For bug reports, please provide the following information:

• Zim commit ref: 6cb9d54
• Zsh version: 5.2
• $(uname -mosr): Linux 4.5.1-1-ARCH x86_64 GNU/Linux

Arch Linux, zim installed via AUR PKGBUILD (zsh-zim-git)

Description

prezto offers tab completion of ssh with host names. e.g. if there are hosts defined in ~/.ssh/config, you can tab complete with these. This seems to be missing in zim.

Steps to reproduce

Type in $ ssh f<tab>. Expect host foo to be offered as a completion.

[Eriner]

I do not have this problem. I can tab complete hosts. Please link your .zimrc.

[protist]

I've pared down my ~/.zshrc, ~/.zimrc, and other files to exactly the same as those shipped by zim from the templates directory. I still hit this issue, but I may have described it poorly, so I will clarify.

In ~/.ssh/config, I have several entries such as the following.

Host foo
Hostname bar.com
IdentityFile ~/.ssh/protist@foo
User protist

I can type in ssh <tab>, and tab completion will offer a list of remote host names, including bar.com. However, completing to ssh bar.com will not use settings in ~/.ssh/config. Instead, one should normally connect with ssh foo. This expands the Host using the ssh config, using the correct identity file, port, etc.

Using zsh with zim will not tab complete to these Hosts. OTOH, prezto does offer to complete these Hosts.

[Eriner]

so, it tab completes the hostnames rather than the hosts?

[protist]

Yes. From memory, prezto offers to complete both.

[Eriner]

mine tab completes both.

Completion of remote hosts in menu:
"ssh "

 -- remote host name --
arch.localdomain               github.com                     localhost
arch                           localhost.localdomain          aur.archlinux.org

Tab completion of Host from .ssh/config
"ssh gi"

ssh gitlab

[protist]

With zim:

$ ssh a<tab>
 -- remote host name --
aur.archlinux.org
 -- login name --
avahi

With prezto installed (on top):

$ ssh a<tab>
 -- domain --
aur.archlinux.org
 -- host --
aur

I'm not really sure why the login name disappeared, but it shouldn't have really been in there in the first place.

[protist]

Since I've pared the config files down to your repository versions, it's odd that I see different behaviour to you. Would it be possible for you to post your personal files, so I can try with them?

[Eriner]

My personal files are basically the same as the template files. I haven't touched anything with ssh other than enabling and using the ssh agent feature.

[protist]

FWIW I tried enabling the ssh module, but that didn't make any difference. I followed instructions here to get it working, but I've no idea why it's not working in vanilla zim.

[protist]

Just a note for the code I'm currently using. It's sourced from the link above, but I've removed known_hosts, and added tab-completion for rsync.

h=()
if [[ -r ~/.ssh/config ]]; then
  h=($h ${${${(@M)${(f)"$(cat ~/.ssh/config)"}:#Host *}#Host }:#*[*?]*})
fi
if [[ $#h -gt 0 ]]; then
  zstyle ':completion:*:ssh:*' hosts $h
  zstyle ':completion:*:slogin:*' hosts $h
  zstyle ':completion:*:rsync:*' hosts $h
fi

[PatTheMav]

While I haven't found time to find a fix for this issue I can confirm the reported behavior.

Tab completion delivers known_hosts entries only, but not HOST entries from the SSH config (which contains the necessary combination of hostname, username and identity file).

[Eriner]

If someone wants to follow this up, this seems like a good place to start: http://www.zsh.org/mla/workers/2010/msg00535.html

[ratheesh]

I copied following lines from prezto (modules/completion/init.zsh - L95-99)

zstyle -e ':completion:*:hosts' hosts 'reply=( ${=${=${=${${(f)"$(cat {/etc/ssh_,~/.ssh/known_}hosts(|2)(N) 2>/dev/null)"}%%[#| ]*}//\]:[0-9]*/ }//,/ }//\[/ } ${=${(f)"$(cat /etc/hosts(|)(N) <<(ypcat hosts 2>/dev/null))"}%%\#*} ${=${${${${(@M)${(f)"$(cat ~/.ssh/config 2>/dev/null)"}:#Host *}#Host }:#*\**}:#*\?*}} )'

After including this, ssh hostcompletion from ~/.ssh/config works fine for me.

[PatTheMav]

TBH, I dunno if @Eriner changed anything recently, but for some time now tab autocompletes to my aliases, so I figured that it was fixed somehow quite a while ago..

[protist]

@PatTheMav FWIW it's still broken for me, once I take out my fix from ~/.zshrc.

[neeklamy]

• Zim commit ref: dca1803
• Zsh version: zsh 5.3.1 (x86_64-apple-darwin15.6.0)
• Darwin 15.6.0 x86_64 (10.11.6)

I haven’t made any customisations to Zim.

I do have ssh tab completion, but:

1. If I just ssh <tab> the servers I’ve set up in ~/.ssh/config don’t appear. If I try ssh di<tab>, my DigitalOcean entry from config completes just fine.
2. If an entry in ~/.ssh/known_hosts includes the same name (it ignores any TLDs and capitalisation), then it takes precedence over any related entry in config. So for example:

# known_hosts
digitalocean.com,12.345.67.89 ecdsa-sha2-nistp256 […]

# config
Host DigitalOcean
	HostName 12.345.67.89
	IdentityFile ~/.ssh/id_rsa

Hitting ssh di<tab> will always complete to ssh digitalocean.com On this second point, the fix is easy enough, just remove any domains from known_hosts.

The first issue remains though, recalling a list of configured domains from tab completion doesn’t work.

The code that @protist links to (comment) fixes it though.

[Eriner]

Might be looking into seeing what can be learned from prezto's approach, as well as the issues and resolutions for omz: ohmyzsh/ohmyzsh#4345

[Eriner]

Hi friends, it wouldn't let me tag some of you in the PR, but I believe #294 will solve this problem for everyone by forcing the completion to fallback to the _ssh_hosts builtin ~/.ssh/config parsing. The only downside here is that the matching isn't ideal and it essentially matches by host* and thus IPs are also included in the initial list. Not a big enough deal to prevent PR imo.

[Eriner]

@protist, @PatTheMav, does that PR resolve the issue to your satisfaction?

[lnicola]

@Eriner, for whatever reason, ~/.ssh/config completion is now working for me, even without #294.

[protist]

Thanks @Eriner! I compared the output to my earlier comment, and the host is now offered as an alternative! (To remind us, it's aur in the suggestions below.)

$ ssh a<tab>
-- remote host name --
aur                aur.archlinux.org
-- login name --
avahi

However, TBH I find this an inferior fix than what I have in ~/.zshrc, because it suggests things that I'd prefer not in there, i.e. the hostname aur.archlinux.org, and the login name avahi. In my current code below, it only suggests the host itself.

# ssh tab completion
h=()
if [[ -r ~/.ssh/config ]]; then
  h=($h ${${${(@M)${(f)"$(cat ~/.ssh/config)"}:#Host *}#Host }:#*[*?]*})
fi
if [[ $#h -gt 0 ]]; then
  zstyle ':completion:*:ssh:*' hosts $h
  zstyle ':completion:*:slogin:*' hosts $h
  zstyle ':completion:*:rsync:*' hosts $h
fi
# Prevent autocompletion of user names
zstyle ':completion:*:rsync:*' users
zstyle ':completion:*:ssh:*' users

You can see in my code the part suppressing the login names. I presume there's a way to suppress the plain hostname itself as well. So, long story short, it's definitely better than it was, but I'd probably still need to add code to fit my needs. Thanks again for persisting with this!

[Eriner]

@protist Cool. We can add more zstyle configurables later if necessary, but I believe this fixes the core issue and the built-in _ssh_hosts now behaves as expected and parses ~/.ssh/config and not just known_hosts and /etc/hosts.

Just as a short follow-up, you can define the my_hosts function with your filter to add only the Host xyz entries and not the Hostname entries. The fallthrough to the _ssh_hosts will glob anything like host*, as explained in my previous comment.