The leading `.` is dropped from *extension*, for example to specify the
interpreter for `.pl` files you configure `interpreters.pl` (where `.`
in this case just means "a child of" in the configuration file, however
that is specified in your preferred format).

To change the Python interpreter to `C:\Python39\python3.exe` and add a
Tcl/Tk interpreter, include the following in your config file:

<!-- example-formats -->
```toml title="~/.config/chezmoi/chezmoi.toml"
[interpreters.py]
    command = 'C:\Python39\python3.exe'
[interpreters.tcl]
    command = "tclsh"
```
<!-- /example-formats -->

Note that the TOML version can also be written like this, which
resembles the YAML version more and makes it clear that the key
for each file extension should not have a leading `.`:

```toml title="~/.config/chezmoi/chezmoi.toml"
[interpreters]
py = { command = 'C:\Python39\python3.exe' }
tcl = { command = "tclsh" }
```

PowerShell Core (`pwsh`) must be installed separately on most systems.
If you don't have it installed:

- **Windows**: Download from [PowerShell releases](https://github.com/PowerShell/PowerShell/releases)
  or install via `winget install Microsoft.PowerShell`
- **Linux/macOS**: Follow instructions at [Installing PowerShell](https://learn.microsoft.com/powershell/scripting/install/installing-powershell)

chezmoi defaults to PowerShell Core (`pwsh`) for `.ps1` scripts as it
provides better UTF-8 support and cross-platform compatibility. On Windows,
if `pwsh` is not available, chezmoi will automatically fall back to Windows
PowerShell (`powershell`).

To explicitly use Windows PowerShell instead of the automatic selection,
include the following in your config file:

<!-- example-formats -->
```toml title="~/.config/chezmoi/chezmoi.toml"
[interpreters.ps1]
    command = "powershell"
    args = ["-NoLogo"]
```
<!-- /example-formats -->