Add shelldash Option to Disable -- Appending in Shell Commands

[clappedscant906]

Pull Request: Add shelldash Option to Disable -- Appending in Shell Commands

Summary

This PR adds a new shelldash option to control whether lf appends -- to shell command arguments. This fixes compatibility issues with shells like nushell that do not support the -- argument separator in the same way as traditional POSIX shells.

Problem Description

lf currently unconditionally appends -- to shell command arguments on Unix/Linux systems to prevent arguments from being interpreted as shell options. While this works correctly for POSIX-compliant shells (sh, bash, zsh), it causes errors with nushell.

Example Error with Nushell

lfrc configuration:

set shell nu
set shellflag "-c"
cmd open $echo test

Error when invoking the command:

Error: nu::parser::unknown_flag
× The `nu` command doesn't have flag named empty.
╭─[source:2:3]
" -- nu -c "echo test
·                   ─┬
·                    ╰── unknown flag
╰────
help: Use `--help` to see available flags

The issue is that nushell interprets the -- as a flag (or incorrectly parses it), whereas traditional shells use -- as a standard end-of-options marker.

Solution

Added a new boolean option shelldash that defaults to true (preserving current behavior for existing users). Users working with nushell or other incompatible shells can now disable the -- appending.

After Fix - Working Configuration

set shell nu
set shelldash false
set shellflag "-c"

cmd open $print test; input

This configuration now works correctly - it prints "test" and waits for user input.

Changes Made

File	Change
opts.go	Added shelldash bool field to gOpts struct
opts.go	Set default value gOpts.shelldash = true in init()
eval.go	Added option parsing for shelldash, noshelldash, shelldash!
os.go	Modified shellCommand() to conditionally append -- based on gOpts.shelldash

Key Implementation Detail

Before (os.go):

args = append([]string{gOpts.shellflag, s, "--"}, args...)

After (os.go):

if gOpts.shelldash {
    args = append([]string{gOpts.shellflag, s, "--"}, args...)
} else {
    args = append([]string{gOpts.shellflag, s}, args...)
}

Usage

Users can control the behavior in their lfrc:

# Default behavior (append --)
set shelldash

# Disable the -- appending (for nushell, etc.)
set noshelldash
# or
set shelldash false

# Toggle with !
set shelldash!

Backward Compatibility

• The option defaults to true, so existing configurations continue to work unchanged
• No breaking changes to the API or existing behavior

Testing Environment

• lf version: r40
• nushell version: 0.109.1

Checklist

• Default behavior unchanged (-- is still appended by default)
• set shelldash enables -- appending
• set noshelldash disables -- appending
• set shelldash! toggles the behavior
• Tested with nushell (the primary use case)
• Verified compatibility with POSIX shells (sh, bash)

[CatsDeservePets]

So this is basically aims to fix

• Multishell/Crossplatform handling of -- #1784

There has been an attempt to solve this problem, however the PR was never finished

• feat: temlated shell command #1852

I honestly do prefer the approach suggested by @joelim-work in the original issue as it seems more flexible and potentially also useful for other shells.