dler senv

Inspect and modify environment variables at both process and user-level with cross-platform support.

Usage

dler senv --action <action> [options]

Description

The senv command provides comprehensive environment variable management with support for both temporary process-level changes and persistent user-level modifications. It handles cross-platform differences between Windows and POSIX systems automatically.

Options

Action Control

Variable Control

Persistence

Examples

Listing variables

# List all environment variables
dler senv --action list

# Show specific variable
dler senv --action list --name PATH

Getting values

# Get variable value
dler senv --action get --name NODE_ENV

Setting values

# Set variable for current process and persist to user environment
dler senv --action set --name MY_VAR --value "hello world"

# Set without persistence (process only)
dler senv --action set --name TEMP_VAR --value "temporary" --persist false

# Skip confirmation prompt
dler senv --action set --name MY_VAR --value "value" --yes

Path manipulation

# Add to PATH (cross-platform)
dler senv --action append --name PATH --value "/usr/local/bin"

# Add to PATH on Windows
dler senv --action append --name Path --value "C:\Users\your-user-name\.local\bin"

# Remove from PATH
dler senv --action remove --name PATH --value "/usr/local/bin"

Checking contents

# Check if PATH contains specific directory
dler senv --action contains --name PATH --value "/usr/local/bin"

Actions

list

Display environment variables.

# All variables (alphabetically sorted)
dler senv --action list

# Specific variable
dler senv --action list --name HOME

get

Retrieve the value of a specific environment variable.

dler senv --action get --name NODE_ENV
# Output: development

set

Set an environment variable value.

dler senv --action set --name API_URL --value "https://api.example.com"

By default, changes are persisted to the user environment and applied to the current process.

append

Add an entry to a PATH-like variable (semicolon/colon separated).

# Add directory to PATH
dler senv --action append --name PATH --value "/opt/myapp/bin"

Handles duplicates and maintains proper path separators.

remove

Remove an entry from a PATH-like variable.

# Remove directory from PATH
dler senv --action remove --name PATH --value "/opt/myapp/bin"

contains

Check if a PATH-like variable contains a specific entry.

dler senv --action contains --name PATH --value "/usr/local/bin"
# Exit code: 0 (found) or 1 (not found)

Platform Support

Windows

• Uses PowerShell for user environment modifications
• Handles PATH variable case-insensitively
• Supports both forward and backward slashes
• Creates backups of modified files

POSIX (Linux/macOS)

• Modifies ~/.profile for persistence
• Uses colon (:) as path separator
• Creates timestamped backups
• Handles shell variable escaping

Persistence

User Environment

Changes are persisted to the user environment by default:

• Windows: Registry (user-level environment variables)
• POSIX: ~/.profile with proper export statements

Process Environment

Changes are applied to the current process immediately.

Backup Creation

Before modifying any files, the command creates timestamped backups:

.profile.bak.2024-01-11T10-30-45-123Z.abc123

Safety Features

Confirmation Prompts

• Interactive confirmation before persisting changes
• Can be skipped with --yes flag
• Clear messaging about what will be modified

Backup Creation

• Automatic backup of modified files
• Timestamped and randomized backup names
• Prevents accidental data loss

Duplicate Prevention

• Prevents duplicate entries in PATH-like variables
• Case-insensitive comparison on Windows
• Maintains entry order

Path Handling

Normalization

• Normalizes path separators (forward/backward slashes)
• Trims whitespace
• Removes empty entries

Case Sensitivity

• Windows: Case-insensitive PATH operations
• POSIX: Case-sensitive operations

Separator Handling

• Windows: Uses semicolon (;)
• POSIX: Uses colon (:)

Exit Codes

Requirements

• Bun runtime: This command requires Bun to be available
• Platform-specific tools: PowerShell on Windows, shell access on POSIX
• File system permissions: Write access to profile files and registry

Common Use Cases

Development Setup

# Add local bin directory to PATH
dler senv --action append --name PATH --value "$HOME/.local/bin"

# Set development environment
dler senv --action set --name NODE_ENV --value "development"

Tool Installation

# Add tool to PATH after installation
dler senv --action append --name PATH --value "/opt/my-tool/bin"

Temporary Overrides

# Temporary environment override (process only)
dler senv --action set --name DEBUG --value "*" --persist false

Troubleshooting

Permission Issues

• Ensure write access to profile files (~/.profile)
• On Windows, run as administrator for system-wide changes
• Check PowerShell execution policy

Path Issues

• Use absolute paths when possible
• Verify path separators match platform conventions
• Check for conflicting entries

Persistence Problems

• Verify backup files weren't corrupted
• Check shell configuration loading
• Restart shell sessions after changes