penv

Pentester Environment - A CLI tool for managing network and customer-specific environment variables across shell sessions on Linux.

Overview

penv auto-discovers network configuration and exposes it as shell variables. It supports saving/loading profiles for different customer environments, making it easy to switch contexts during engagements.

Variables are stored in ~/.local/share/penv/current.yaml and exported as lowercase shell variables (e.g., $ip, $dc, $domain) for direct use in commands like:

nxc smb $dc -d $domain -u $user -p $password

Installation

cargo build --release
cp target/release/penv ~/.local/bin/

Shell Setup

Add to your .bashrc or .zshrc:

eval "$(penv shell-init)"

This installs a wrapper function that:

• Exports all variables from current.yaml on shell startup
• Auto-reloads variables after penv set, penv unset, penv load, or penv discover

For fish shell:

eval (penv shell-init fish)

Manual mode: If you prefer explicit control, use eval "$(penv init)" instead. You'll need to re-run it after each change.

Usage

Auto-discover network environment

penv discover

Detects and saves:

• ip - Local IP of the primary LAN adapter
• gateway - Default gateway
• dc - DNS server (useful as DC in AD environments)
• domain - DNS search domain

Manage variables

penv set user "USERNAME"
penv set password "P@ssw0rd!"
penv unset password
penv list

Profile management

Save the current configuration as a named profile:

penv store customer_1

Load a saved profile:

penv load customer_1

With shell-init, variables are reloaded automatically.

Profiles are stored as ~/.local/share/penv/<name>.yaml.

Shell completions

Generate completions for your shell:

# Bash
penv completions bash > ~/.local/share/bash-completion/completions/penv

# Zsh
penv completions zsh > ~/.zfunc/_penv

# Fish
penv completions fish > ~/.config/fish/completions/penv.fish

Commands

Command	Description
penv init	Output export commands for eval
penv shell-init [shell]	Output shell wrapper with auto-reload (bash/zsh/fish)
penv discover	Auto-detect network info and save to current.yaml
penv set <key> <value>	Add or update a variable
penv unset <key>	Remove a variable
penv list	Print all active variables
penv clean	Wipe current.yaml
penv store <name>	Save current state as a profile
penv load <name>	Load a profile into current.yaml
penv completions <shell>	Generate shell completions

Configuration Files

• ~/.local/share/penv/current.yaml - Active configuration
• ~/.local/share/penv/<profile>.yaml - Saved profiles

Example YAML:

vars:
  ip: 192.168.1.50
  gateway: 192.168.1.1
  dc: 192.168.1.10
  domain: corp.local
  user: administrator

Network Discovery

Discovery uses standard Linux tools with automatic fallbacks:

IP and Gateway:

• ip route - Default route interface and gateway
• ip addr - IP address of the default route interface

DNS Server and Domain (tried in order, merges results):

1. resolvectl - systemd-resolved (only if active)
2. nmcli - NetworkManager
3. DHCP lease files:
   • /run/systemd/netif/leases/<ifindex> (systemd-networkd)
   • /var/lib/dhcp/dhclient.*.leases (dhclient)
4. /run/systemd/resolve/resolv.conf - upstream DNS when using systemd stub
5. /etc/resolv.conf - classic fallback

Works on systems with systemd-networkd, systemd-resolved, NetworkManager, dhclient, or plain resolv.conf.

License

MIT - see LICENSE