How to find out it is Wayland or X system?

[Archie-2021]

Is there a way to get which one is running on the system?

[halostatue]

This is not really a chezmoi question, as this is well-answered on Stack Overflow. However, there are some complicating factors to how you would run such a complex command-line from within a chezmoi template.

NOTE: I don't use Linux as my daily driver, so I don't know whether the commands here will actually work, as I have nothing to test them on.

Here's the command-line we should use from the SO post in question:

loginctl show-session $(loginctl | grep $(whoami) | awk '{print $1}') -p Type

First, you will need to use the output template function, which requires each command be quoted, but does not know how to run sub-shells or piped commands. This could be written as:

{{ output "bash" "-c" "'loginctl show-session $(loginctl | grep $(whoami) | awk \\'{ print $1 }\\') -p Type'" }}

This will probably work, but the levels of quoting required are particularly difficult to read, so the following (more complex) template should also work:

{{- $whoami := output "whoami" | trim -}}{{/* $(whoami) */}}
{{- $sessions := output "loginctl" | jq "split(\"\\n\")" | first - }}{{/* loginctl | */}}
{{- $mySessionPattern := printf "map(select(match(\"%s\"))).[0]" $whoami -}}
{{- $mySession = jq $mySessionPattern $sessions | splitList " " | first -}}{{/* grep $whoami | awk print $1 */}}
{{- output "loginctl" "show-session" $mySession "-p" "Type" -}}

There are other ways to break this down using printf and multiple executions of bash -c "…".

Your other option is to make a shell script that runs loginctl show-session $(loginctl | grep $(whoami) | awk '{print $1}') -p Type and then just do output "my-current-session-type" in your template to get that value.

[Archie-2021]

Thanks, could not find running bash commands in documentation so I though I should ask for an internal command.

This opens up a lot of options and more uses out of this amazing app.

[Archie-2021]

This is not really a chezmoi question, as this is well-answered on Stack Overflow. However, there are some complicating factors to how you would run such a complex command-line from within a chezmoi template.

NOTE: I don't use Linux as my daily driver, so I don't know whether the commands here will actually work, as I have nothing to test them on.

Here's the command-line we should use from the SO post in question:

loginctl show-session $(loginctl | grep $(whoami) | awk '{print $1}') -p Type

First, you will need to use the output template function, which requires each command be quoted, but does not know how to run sub-shells or piped commands. This could be written as:

{{ output "bash" "-c" "'loginctl show-session $(loginctl | grep $(whoami) | awk \\'{ print $1 }\\') -p Type'" }}

This will probably work, but the levels of quoting required are particularly difficult to read, so the following (more complex) template should also work:

{{- $whoami := output "whoami" | trim -}}{{/* $(whoami) */}}
{{- $sessions := output "loginctl" | jq "split(\"\\n\")" | first - }}{{/* loginctl | */}}
{{- $mySessionPattern := printf "map(select(match(\"%s\"))).[0]" $whoami -}}
{{- $mySession = jq $mySessionPattern $sessions | splitList " " | first -}}{{/* grep $whoami | awk print $1 */}}
{{- output "loginctl" "show-session" $mySession "-p" "Type" -}}

There are other ways to break this down using printf and multiple executions of bash -c "…".

Your other option is to make a shell script that runs loginctl show-session $(loginctl | grep $(whoami) | awk '{print $1}') -p Type and then just do output "my-current-session-type" in your template to get that value.

Hey, I finally found sometime to mess with this config. I put it in a script and it work when I use output command. But I need to put it in an if statement and mix it with with if and and commands. I tried many ways including of course using round brackets but it didn't work. Can you try to see how I can check the returned value?

Thanks

[twpayne]

Can you try to see how I can check the returned value?

You need to show what you tried.

[Archie-2021]

Can you try to see how I can check the returned value?

You need to show what you tried.

I tried something like this:

{{ if ( eq ( ( output "my-script.sh") "Type=x11" ) ) }}

I used parentheses to contain it, but this if statement value is false every time, and if I remove it it just try to interpret "Type=x11" part as shell command s and errors.

[halostatue]

I have a couple of suggestions. For investigation, remember chezmoi execute-template. In this case, chezmoi execute-template '{{ output "my-script.sh" }}'.

My immediate thought is that this is failing because chezmoi doesn't know where to find my-script.sh. You probably want to put this in .chezmoi.workingTree (that’s your chezmoi git directory, and is not the same as .chezmoi.sourceDir, which may be affected by the presence of .chezmoiroot in the working tree) and run this as output (joinPath .chezmoi.workingTree "my-script.sh"). I would also suggest that you give the script a better name. It's also likely that it would be better to put the comparison in your script. Assuming that it’s more or less what was done before:

#! /usr/bin/env bash

set -euo pipefail

session="$(loginctl | grep "${USER:-$(whoami)} | awk '{ print $1 }')"
session_type="$(loginctl show-session "${session}" -p Type)"

[[ "${1:-}" == "${session_type}" ]] && echo true

This would now be called as if output (joinPath .chezmoi.workingTree "login-session-type-is" "Type=x11") … if output (joinPath .chezmoi.workingTree "login-session-type-is") "Type=x11" assuming that you name the script login-session-type-is and put it in .chezmoi.workingTree. In Go, "" is a false, so because the script doesn't output anything if $1 doesn't match the discovered $session_type, it would fall to the else condition.

I reiterate: take my suggestions here with a huge grain of salt. I don't have a Linux desktop machine at all, so I can't say that what I have written will actually work in your case. But the logic involved I can attest to. As Knuth said, "Beware of bugs in the above code; I have only proved it correct, not tried it".

[Archie-2021]

I have a couple of suggestions. For investigation, remember chezmoi execute-template. In this case, chezmoi execute-template '{{ output "my-script.sh" }}'.

My immediate thought is that this is failing because chezmoi doesn't know where to find my-script.sh. You probably want to put this in .chezmoi.workingTree (that’s your chezmoi git directory, and is not the same as .chezmoi.sourceDir, which may be affected by the presence of .chezmoiroot in the working tree) and run this as output (joinPath .chezmoi.workingTree "my-script.sh"). I would also suggest that you give the script a better name. It's also likely that it would be better to put the comparison in your script. Assuming that it’s more or less what was done before:

#! /usr/bin/env bash

set -euo pipefail

session="$(loginctl | grep "${USER:-$(whoami)} | awk '{ print $1 }')"
session_type="$(loginctl show-session "${session}" -p Type)"

[[ "${1:-}" == "${session_type}" ]] && echo true

This would now be called as if output (joinPath .chezmoi.workingTree "login-session-type-is" "Type=x11") … assuming that you name the script login-session-type-is and put it in .chezmoi.workingTree. In Go, "" is a false, so because the script doesn't output anything if $1 doesn't match the discovered $session_type, it would fall to the else condition.

I reiterate: take my suggestions here with a huge grain of salt. I don't have a Linux desktop machine at all, so I can't say that what I have written will actually work in your case. But the logic involved I can attest to. As Knuth said, "Beware of bugs in the above code; I have only proved it correct, not tried it".

Hey, and thanks for your help again

I don't think the path is the issue. I have tried {{ output "myscript" }} with chezmoi execute-template command you mentioned before and it was printing the stdout perfectly. Altho it is a good idea to do the all stuff in bash including testing with if I don't think it is the problem. I think it can not pars the commands in order. I tried what you have suggested (put myscript in ~/.local/share/chezmoi but it is giving me this error ( It tried to Joinpath the argumnet for script to path too)

chezmoi: template: stdin:1:6: executing "stdin" at <output (joinPath .chezmoi.workingTree "test-mysc000" "Type=x11")>: error calling output: ~/.local/share/chezmoi/test-mysc000/Type=x11: fork/exec ~/.local/share/chezmoi/test-mysc000/Type=x11: not a directory

It is the template I tested on it:

{{ if output (joinPath .chezmoi.workingTree "test-mysc000" "Type=x11") }}
Printing True
{{ else }}
Printing False
{{ end }}

[halostatue]

Ah. There’s a typo in what I wrote (as I said, I hadn’t run any of it):

{{ if output (joinPath .chezmoi.workingTree "test-mysc000") "Type=x11" }}
Printing True
{{ else }}
Printing False
{{ end }}

[Archie-2021]

Ah. There’s a typo in what I wrote (as I said, I hadn’t run any of it):

{{ if output (joinPath .chezmoi.workingTree "test-mysc000") "Type=x11" }}
Printing True
{{ else }}
Printing False
{{ end }}

Excellent, you were right. The issue was finding path and now it is works like a charm.

Thank you very much for your help

[trinitronx]

Another way is to check for the existence of wayland-scanner or XDG_SESSION_TYPE equal to "wayland" on Linux. This works because on most distros, wayland-scanner is installed alongside libwayland or at least $XDG_SESSION_TYPE is set. For example:

In .chezmoi.yaml.tmpl, set a data variable to hold XDG_SESSION_TYPE:

{{- $xdg_session_type := "" -}}
{{- if hasKey . "xdg_session_type" -}}
{{-   $xdg_session_type = .xdg_session_type -}}
{{- else if (env "XDG_SESSION_TYPE") -}}
{{-   $xdg_session_type = env "XDG_SESSION_TYPE" -}}
{{- end -}}

# ... other stuff ...

data:
  xdg_session_type: "{{ $xdg_session_type }}"

Then, in a template:

{{ if (eq .chezmoi.os "linux") | and ((lookPath "wayland-scanner") | or (eq .xdg_session_type "wayland")) -}}
# ... wayland specific stuff ...
{{ else -}}
# ... other non-Wayland stuff ...
{{ end -}}

Note that only $XDG_SESSION_TYPE is tied to whether the current session is Wayland or not. Meanwhile. the wayland-scanner binary could still exist on a system with Wayland and other desktops (KDE, GNOME, Cinnamon, etc...) if the current session was something else.

For passively installing configs on a system that might run Wayland sessions, using the above check is usually fine in practice. For things that depend on the current session being Wayland actively, (warning: non-hermetic / tied to current session at runtime) the $XDG_SESSION_TYPE check alone would work.