bssh - Broadcast SSH

Recent Updates

Features

Installation

Install via Homebrew (macOS/Linux)

brew tap lablup/tap
brew install bssh

Install via Ubuntu PPA

# Add the PPA repository
sudo add-apt-repository ppa:lablup/backend-ai
sudo apt update
# Install bssh
sudo apt install bssh

Install via Debian Package

# Download the latest .deb package (replace VERSION with the actual version)
wget https://github.com/lablup/bssh/releases/download/vVERSION/bssh_VERSION_OS_ARCH.deb
# Example: bssh_0.4.0_ubuntu24.04.noble_amd64.deb
# Install the package
sudo dpkg -i bssh_VERSION_OS_ARCH.deb
# If there are dependency issues, fix them with:
sudo apt-get install -f

Download Pre-built Binary

Install from Cargo

cargo build --release
sudo cp target/release/bssh /usr/local/bin/

Quick Start

SSH-Compatible Mode (Single Host)

# Connect to a host (just like SSH!)
bssh user@hostname
# Execute a command
bssh user@hostname "uptime"
# With specific port and key
bssh -p 2222 -i ~/.ssh/key.pem admin@server.com
# Using SSH options
bssh -o StrictHostKeyChecking=no user@host
# Query SSH capabilities
bssh -Q cipher

Port Forwarding

# Local port forwarding (-L)
# Forward local port 8080 to example.com:80 via SSH
bssh -L 8080:example.com:80 user@host
# Remote port forwarding (-R) 
# Forward remote port 8080 to localhost:80
bssh -R 8080:localhost:80 user@host
# Dynamic port forwarding / SOCKS proxy (-D)
# Create SOCKS5 proxy on local port 1080
bssh -D 1080 user@host
# Multiple port forwards
bssh -L 3306:db:3306 -R 80:web:80 -D 1080 user@host
# Bind to specific address
bssh -L 127.0.0.1:8080:web:80 user@host # Local only
bssh -L *:8080:web:80 user@host # All interfaces
# SOCKS4 proxy (specify version)
bssh -D 1080/4 user@host # SOCKS4
bssh -D *:1080/5 user@host # SOCKS5 on all interfaces
# Port forwarding with command execution
bssh -L 5432:postgres:5432 user@host "psql -h localhost"
# Port forwarding with cluster operations
bssh -C production -L 8080:internal:80 "curl http://localhost:8080"

Jump Host Support (ProxyJump)

# Connect through a single jump host (bastion)
bssh -J jump@bastion.example.com user@internal-server
# Multiple jump hosts (connection chain)
bssh -J "jump1@proxy1,jump2@proxy2" user@final-destination
# Jump host with custom port
bssh -J admin@bastion:2222 user@internal-host
# IPv6 jump host
bssh -J "[2001:db8::1]:22" user@destination
# Combine with cluster operations
bssh -J bastion.example.com -C production "uptime"
# File transfer through jump host
bssh -J bastion.example.com -H internal-server upload app.tar.gz /opt/
bssh -J admin@bastion:2222 -C production download /etc/config ./backups/
# Interactive mode through jump hosts
bssh -J bastion.example.com user@internal-server
bssh -J "jump1,jump2" -C production interactive
# Multi-hop with file transfer
bssh -J "bastion1,bastion2,bastion3" -H target upload -r ./app/ /opt/app/

Multi-Server Mode (Cluster Operations)

# Execute commands on multiple hosts (automatic command execution)
bssh -H "user1@host1.com,user2@host2.com:2222" "uptime"
# Using cluster from config
bssh -C production "df -h"
# Hostlist expressions (pdsh-style range expansion)
bssh -H "node[1-5]" "uptime" # node1, node2, node3, node4, node5
bssh -H "node[01-05]" "df -h" # Zero-padded: node01, node02, ...
bssh -H "node[1,3,5]" "ps aux" # Specific values: node1, node3, node5
bssh -H "rack[1-2]-node[1-3]" "uptime" # Cartesian product: 6 hosts
bssh -H "web[1-3].example.com" "nginx -v" # With domain suffix
bssh -H "admin@db[01-03]:5432" "psql --version" # With user and port
bssh -H "^/etc/hosts.cluster" "uptime" # Read hosts from file
# Filter specific hosts with pattern matching
bssh -H "web1,web2,db1,db2" -f "web*" "systemctl status nginx"
bssh -C production -f "db*" "pg_dump --version"
bssh -H "node[1-10]" -f "node[1-5]" "uptime" # Filter with hostlist expression
# Exclude specific hosts from execution
bssh -H "node1,node2,node3" --exclude "node2" "uptime"
bssh -C production --exclude "db*" "systemctl restart nginx"
bssh -H "node[1-10]" --exclude "node[3-5]" "uptime" # Exclude with hostlist expression
# With custom SSH key
bssh -C staging -i ~/.ssh/custom_key "systemctl status nginx"
# Use SSH agent for authentication
bssh -A -C production "systemctl status nginx"
# Use password authentication (will prompt for password)
bssh --password -H "user@host.com" "uptime"
# Use sudo password for privileged commands (prompts securely)
bssh -S -C production "sudo apt update && sudo apt upgrade -y"
# Combine sudo password with SSH agent authentication
bssh -A -S -C production "sudo systemctl restart nginx"
# Use encrypted SSH key (will prompt for passphrase)
bssh -i ~/.ssh/encrypted_key -C production "df -h"
# Limit parallel connections
bssh -C production --parallel 5 "apt update"
# Set command timeout (10 seconds)
bssh -C production --timeout 10 "quick-check"
# No timeout (unlimited execution time)
bssh -C staging --timeout 0 "long-running-backup"
# Set connection timeout (default: 30 seconds)
bssh -C production --connect-timeout 10 "uptime"
# Different timeouts for connection and command
bssh -C production --connect-timeout 5 --timeout 600 "long-running-job"
# Configure SSH keepalive (prevent idle connection timeouts)
bssh -C production --server-alive-interval 30 "long-running-job"
# Disable keepalive (set interval to 0)
bssh -C production --server-alive-interval 0 "quick-job"
# Keepalive with custom max retries (default: 3)
bssh -C production --server-alive-interval 30 --server-alive-count-max 5 "long-running-job"
# Fail-fast mode: stop immediately on any failure (pdsh -k compatible)
bssh -k -H "web1,web2,web3" "deploy.sh"
bssh --fail-fast -C production "critical-script.sh"
# Combine fail-fast with require-all-success for critical operations
bssh -k --require-all-success -C production "service-restart.sh"

Output Modes

TUI Mode (Default in Terminals)

# TUI mode automatically activates for multi-node commands
bssh -C production "apt-get update"
# Features:
# - Summary view: All nodes at a glance with progress bars
# - Detail view: Full output from specific node with scrolling
# - Split view: Monitor 2-4 nodes simultaneously in panes
# - Diff view: Compare output from two nodes side-by-side
# - Auto-scroll: Automatic following of new output
# - Progress detection: Percentage, fraction, apt/dpkg indicators
# - Real-time updates: Output streams in real-time (50ms polling)
# - Memory protection: 10MB buffer per node with graceful overflow

Stream Mode (Real-time with Node Prefixes)

# Enable stream mode explicitly
bssh -C production --stream "tail -f /var/log/syslog"
# Output:
# [node1] Oct 30 10:15:23 systemd[1]: Started nginx.service
# [node2] Oct 30 10:15:24 kernel: [UFW BLOCK] IN=eth0 OUT=
# [node1] Oct 30 10:15:25 nginx: Configuration test successful
# Stream mode without hostname prefix (pdsh -N compatibility)
bssh -C production --stream --no-prefix "uname -a"
# Output (no [node] prefixes):
# Linux node1 5.15.0-generic
# Linux node2 5.15.0-generic

File Mode (Save to Per-Node Files)

# Save each node's output to timestamped files
bssh -C production --output-dir ./logs "ps aux"
# Creates:
# ./logs/node1_20251030_101523.stdout
# ./logs/node2_20251030_101523.stdout
# ./logs/node1_20251030_101523.stderr (if there are errors)

Normal Mode (Traditional Output)

# Automatically used when output is piped or redirected
bssh -C production "uptime" | tee results.txt
bssh -C production "df -h" > disk-usage.log
# Manually disable TUI in terminals
CI=true bssh -C production "command"

Batch Mode (Ctrl+C Handling)

# Default behavior (two-stage Ctrl+C)
bssh -C production "long-running-command"
# Ctrl+C once: shows status
# Ctrl+C again (within 1s): terminates
# Batch mode (immediate termination)
bssh -C production -b "long-running-command"
# Ctrl+C once: immediately terminates all jobs
# Useful for automation
bssh -H nodes --batch --stream "deployment-script.sh"

pdsh Compatibility Mode

Activation Methods

# Create symlink (done automatically by Homebrew)
sudo ln -sf "$(which bssh)" /usr/local/bin/pdsh
# Now pdsh commands use bssh
pdsh -w host1,host2 "uptime"

BSSH_PDSH_COMPAT=1 bssh -w host1,host2 "uptime"

bssh --pdsh-compat -w host1,host2 "uptime"

# Add to ~/.bashrc or ~/.zshrc
alias pdsh='bssh --pdsh-compat'

pdsh Option Mapping

pdsh Mode Examples

# Basic command execution
pdsh -w node1,node2,node3 "uptime"
# With fanout limit
pdsh -w nodes -f 10 "df -h"
# Exclude specific hosts
pdsh -w node[1-5] -x node3 "hostname"
# Query mode: show target hosts without executing
pdsh -w host1,host2,host3 -x host2 -q
# Output:
# host1
# host3
# Combine multiple options
pdsh -w servers -f 20 -l admin -t 30 -N "systemctl status nginx"
# Fail fast mode
pdsh -w nodes -k "critical-operation.sh"

Query Mode with Glob Patterns

# Exclude hosts matching a pattern
pdsh -w web1,web2,db1,db2 -x "db*" -q
# Output:
# web1
# web2
# Use wildcards in exclusion
pdsh -w node1,node2,backup1,backup2 -x "*backup*" -q
# Output:
# node1
# node2

Built-in Commands

# Test connectivity to hosts
bssh -C production ping
bssh -H "host1,host2" ping
# List configured clusters
bssh list
# Interactive mode (single or multiplexed)
bssh -C production interactive
bssh -H "host1,host2" interactive
# File transfer operations
bssh -C production upload local.txt /tmp/
bssh -H "host1,host2" download /etc/hosts ./backups/

Breaking Changes in v1.2.0

What Changed

Migration Guide

# Now returns actual exit codes: 0, 139 (SIGSEGV), 137 (OOM), etc.
bssh exec "mpirun ./simulation"

# v1.0-v1.1
bssh exec "health-check"
# v1.2.0+ (preserve old behavior)
bssh --require-all-success exec "health-check"

Available Strategies

Authentication

SSH Key Authentication

SSH Agent

Password Authentication

Examples

# Use default SSH key (auto-detect)
bssh -H "user@host" "uptime"
# Use specific SSH key (prompts for passphrase if encrypted)
bssh -i ~/.ssh/custom_key -c production "df -h"
# Use SSH agent
bssh -A -c production "systemctl status"
# Use password authentication
bssh -P -H "user@host" "ls -la"
# Authentication through jump hosts
bssh -A -J bastion.example.com user@internal-server "uptime"
bssh -i ~/.ssh/prod_key -J "jump1,jump2" -C production "df -h"

Sudo Password Support

# Basic sudo command (will prompt for sudo password)
bssh -S -C production "sudo apt update"
# Combine with SSH agent authentication
bssh -A -S -C production "sudo systemctl restart nginx"
# Multiple sudo commands in a single session
bssh -S -C production "sudo apt update && sudo apt upgrade -y"
# Sudo with specific SSH key
bssh -i ~/.ssh/admin_key -S -C production "sudo reboot"

# NOT RECOMMENDED for security reasons
export BSSH_SUDO_PASSWORD="your-password"
bssh -S -C production "sudo apt update"

Environment Variables

Jump Host Configuration

Backend.AI Integration Variables

SSH Authentication Variables

SSH Password Variable

Sudo Password Variable

Configuration

Configuration Priority Order

Backend.AI Multi-node Session Support

# Inside Backend.AI multi-node session, just run:
bssh "uptime" # Automatically executes on all cluster nodes
# Or specify a command explicitly:
bssh "nvidia-smi" # Check GPU status on all nodes
# Interactive mode also works automatically:
bssh interactive # Opens interactive session with all Backend.AI nodes
# You can still override with explicit options if needed:
bssh -C other-cluster "command" # Use a different cluster
bssh -H specific-host "command" # Use specific host

Manual Configuration File

defaults:
 user: admin
 port: 22
 ssh_key: ~/.ssh/id_rsa
 parallel: 10
 timeout: 300 # Command timeout in seconds (0 for unlimited)
 jump_host: bastion.example.com # Global default jump host (optional)
 server_alive_interval: 30 # SSH keepalive interval in seconds (0 to disable)
 server_alive_count_max: 3 # Max keepalive messages without response
# Global interactive mode settings (optional)
interactive:
 default_mode: multiplex # single_node or multiplex
 prompt_format: "[{node}] $ " # Variables: {node}, {user}, {host}, {pwd}
 history_file: ~/.bssh_history
 show_timestamps: false # Show timestamps in output
 work_dir: /home/admin # Initial working directory
 broadcast_prefix: "!all " # Prefix for broadcasting to all nodes
 node_switch_prefix: "!" # Prefix for special commands
 colors: # Node-specific colors in output
 node1: red
 node2: blue
 node3: green
 keybindings:
 switch_node: "Ctrl+N"
 broadcast_toggle: "Ctrl+B"
 quit: "Ctrl+Q"
clusters:
 production:
 nodes:
 - web1.example.com
 - web2.example.com
 - user@web3.example.com:2222
 ssh_key: ~/.ssh/prod_key
 timeout: 600 # Override default timeout for this cluster
 jump_host: prod-bastion.example.com # Cluster-specific jump host
 # Cluster-specific interactive settings (overrides global)
 interactive:
 default_mode: single_node
 prompt_format: "prod> "
 work_dir: /var/www
 staging:
 nodes:
 - host: staging1.example.com
 port: 2200
 user: deploy
 jump_host: staging-bastion:2222 # Node-specific jump host
 - staging2.example.com
 user: staging_user
 jump_host: "" # Explicitly disable jump host for this cluster

Jump Host Configuration in config.yaml

defaults:
 jump_host: ${BASTION_HOST} # Environment variables supported
clusters:
 production:
 nodes:
 - host: prod1.internal
 - host: prod2.internal
 jump_host: "" # Explicitly disable for this node
 jump_host: prod-bastion.example.com
 direct-access:
 nodes:
 - host: direct.example.com
 jump_host: "" # Empty string disables inheritance

clusters:
 internal:
 nodes:
 - 192.168.0.100
 user: admin # Used for destination (192.168.0.100)
 jump_host: bai@bastion # User 'bai' for bastion (jump host)

SSH Configuration Support

Certificate Authentication Options

Port Forwarding Control Options

Proxy Options

Command Execution and Automation Options

Host Key Verification & Security Options

Additional Authentication Options

Network & Connection Options

X11 Forwarding Options

Authentication and Security Management Options

SSH Config Examples

Certificate-based Authentication

# ~/.ssh/config
# Production servers with certificate authentication
Host *.prod.example.com
 User admin
 CertificateFile ~/.ssh/prod-user-cert.pub
 CertificateFile ~/.ssh/prod-host-cert.pub
 CASignatureAlgorithms ssh-ed25519,rsa-sha2-512,rsa-sha2-256
 HostbasedAuthentication yes
 HostbasedAcceptedAlgorithms ssh-ed25519,rsa-sha2-512

Strict Port Forwarding Control

# Secure hosts with restricted port forwarding
Host *.secure.prod.example.com
 GatewayPorts clientspecified
 ExitOnForwardFailure yes
 PermitRemoteOpen localhost:8080
 PermitRemoteOpen db.internal:5432
 PermitRemoteOpen cache.internal:6379

Proxy Connection Optimization

# Optimized proxy connection with file descriptor passing
Host internal-server
 ProxyCommand nc -X connect -x proxy.example.com:1080 -F %h %p
 ProxyUseFdpass yes
# SOCKS proxy with netcat (reduces overhead)
Host *.internal.example.com
 ProxyCommand nc -x socks.example.com:1080 -F %h %p
 ProxyUseFdpass yes
# Jump host with ProxyCommand and fd passing
Host bastion-optimized
 ProxyCommand ssh -W %h:%p jump.example.com
 ProxyUseFdpass yes

Command Execution and Automation

# Development server with automatic file synchronization
Host dev-server
 User developer
 PermitLocalCommand yes
 LocalCommand rsync -av ~/project/ %h:~/project/
# Auto-attach to tmux session on connection
Host project-server
 RemoteCommand tmux attach -t project || tmux new -s project
 RequestTTY yes
# Cloud instances with dynamic host key fetching
Host *.cloud.example.com
 KnownHostsCommand /usr/local/bin/fetch-cloud-key %H
 StrictHostKeyChecking accept-new
# Background SSH tunnel for port forwarding
Host tunnel
 ForkAfterAuthentication yes
 SessionType none
 LocalForward 8080 internal-server:80
 StdinNull yes

Host Key Verification, Authentication, and Network Options

# Local development environment - skip localhost verification
Host localhost 127.0.0.1 ::1
 NoHostAuthenticationForLocalhost yes
 NumberOfPasswordPrompts 1
# Security-hardened configuration with host key protection
Host *.secure.example.com
 HashKnownHosts yes
 VisualHostKey yes
 VerifyHostKeyDNS ask
 UpdateHostKeys ask
 CheckHostIP no
# Load-balanced service with shared host key
Host lb-node-*
 HostKeyAlias lb.example.com
# Multi-homed host with specific interface binding
Host vpn-only
 BindInterface tun0
 IPQoS lowdelay throughput
# High-security session with frequent rekeying
Host sensitive-data
 RekeyLimit 500M 30m
# X11 forwarding with timeout and trust for graphics workstation
Host graphics-workstation
 ForwardX11 yes
 ForwardX11Trusted yes
 ForwardX11Timeout 2h

Authentication and Security Best Practices

# Multi-account setup - prevent agent key conflicts
Host work
 HostName work.example.com
 IdentityFile ~/.ssh/work_rsa
 IdentitiesOnly yes
Host personal
 HostName github.com
 User git
 IdentityFile ~/.ssh/personal_ed25519
 IdentitiesOnly yes
# Auto-add keys to SSH agent for convenience
Host *
 AddKeysToAgent yes
# macOS-specific: Use Keychain for SSH key passphrases
# For cross-platform configs, add IgnoreUnknown to prevent errors on non-macOS systems
Host *
 IgnoreUnknown UseKeychain
 UseKeychain yes
# Custom SSH agent integration (1Password, gpg-agent)
Host secure-*
 IdentityAgent ~/.1password/agent.sock
# Disable SSH agent for specific hosts
Host no-agent-host
 IdentityAgent none
# Security-hardened production servers
Host *.prod.example.com
 # Only allow modern, secure algorithms
 PubkeyAcceptedAlgorithms ssh-ed25519,rsa-sha2-512,rsa-sha2-256
 # Enforce strong RSA keys
 RequiredRSASize 2048
 # Use modern fingerprint hashing
 FingerprintHash sha256
# Legacy system compatibility
Host legacy.example.com
 # Allow older RSA keys
 RequiredRSASize 1024
 # Use MD5 for legacy fingerprint verification
 FingerprintHash md5

Complete Example with Include and Match

# Base security settings
Host *
 HostbasedAuthentication no
 ExitOnForwardFailure no
 PermitLocalCommand no
# Production certificate configuration
Host *.prod.example.com
 CertificateFile ~/.ssh/prod-cert.pub
 CASignatureAlgorithms ssh-ed25519,rsa-sha2-512
 HostbasedAuthentication yes
# Match directive for secure hosts
Match host *.secure.prod.example.com
 GatewayPorts clientspecified
 ExitOnForwardFailure yes
 PermitRemoteOpen localhost:8080
# Development hosts with automation
Match host *.dev.example.com
 PermitLocalCommand yes
 LocalCommand notify-send "Connected to %h"
# Specific host overrides
Host web.secure.prod.example.com
 User webadmin
 Port 443
 CertificateFile ~/.ssh/web-specific-cert.pub

Using SSH Config with bssh

# Use default SSH config (~/.ssh/config)
bssh user@host.prod.example.com
# Use custom SSH config file
bssh -F ~/custom-ssh-config user@host.prod.example.com
# SSH config works with cluster operations
bssh -C production "uptime"
# Config options apply to all cluster nodes
bssh -F ~/.ssh/prod-config -C production upload app.tar.gz /opt/

Command-Line Options

Options:
 -H, --hosts <HOSTS> Comma-separated list of hosts (user@host:port format)
 -C, --cluster <CLUSTER> Cluster name from configuration file
 -f, --filter <PATTERN> Filter hosts by pattern (supports wildcards like 'web*')
 --exclude <HOSTS> Exclude hosts from target list (comma-separated, supports wildcards)
 --config <CONFIG> Configuration file path [default: ~/.config/bssh/config.yaml]
 -u, --user <USER> Default username for SSH connections
 -i, --identity <IDENTITY> SSH private key file path (prompts for passphrase if encrypted)
 -A, --use-agent Use SSH agent for authentication (Unix/Linux/macOS only)
 -P, --password Use password authentication (will prompt for password)
 -S, --sudo-password Prompt for sudo password to auto-respond to sudo prompts
 -J, --jump-host <JUMP_HOSTS> Jump hosts: [user@]host[:port],... (uses local user if not specified)
 -L, --local-forward <SPEC> Local port forwarding [bind_address:]port:host:hostport
 -R, --remote-forward <SPEC> Remote port forwarding [bind_address:]port:host:hostport
 -D, --dynamic-forward <SPEC> Dynamic port forwarding (SOCKS) [bind_address:]port[/version]
 --strict-host-key-checking <MODE> Host key checking mode (yes/no/accept-new) [default: accept-new]
 -p, --parallel <PARALLEL> Maximum parallel connections [default: 10]
 --timeout <TIMEOUT> Command timeout in seconds (0 for unlimited) [default: 300]
 --connect-timeout <SECONDS> SSH connection timeout in seconds (minimum: 1) [default: 30]
 --server-alive-interval <SECONDS> SSH keepalive interval in seconds (0 to disable) [default: 30]
 --server-alive-count-max <COUNT> Max keepalive messages without response [default: 3]
 --output-dir <OUTPUT_DIR> Output directory for command results
 -N, --no-prefix Disable hostname prefix in output (pdsh -N compatibility)
 -v, --verbose Increase verbosity (-v, -vv, -vvv)
 -h, --help Print help
 -V, --version Print version

Examples

Backend.AI Multi-node Session

# Inside Backend.AI session - automatic cluster detection
bssh "hostname" # Shows hostnames of all nodes
bssh "nvidia-smi --query-gpu=name,memory.total --format=csv" # GPU info
bssh "python train.py --distributed" # Run distributed training

Run system updates

bssh -C production "sudo apt update && sudo apt upgrade -y"

Check disk usage

bssh -H "server1,server2,server3" "df -h | grep -E '^/dev/'"

Restart services

bssh -C webservers "sudo systemctl restart nginx"

Collect logs

bssh -C production --output-dir ./logs "tail -n 100 /var/log/syslog"

Long-running commands with timeout

# Set 30 minute timeout for backup operations
bssh -C production --timeout 1800 "backup-database.sh"
# No timeout for data migration (may take hours)
bssh -C production --timeout 0 "migrate-data.sh"
# Quick health check with 5 second timeout
bssh -C monitoring --timeout 5 "health-check.sh"

Interactive Mode

# Interactive session on all nodes (multiplex mode - default)
bssh -C production interactive
# Interactive session on a single node
bssh -C production interactive --single-node
# Custom prompt format
bssh -H server1,server2 interactive --prompt-format "{user}@{host}> "
# Set initial working directory
bssh -C staging interactive --work-dir /var/www
# Interactive mode with keepalive for long-running sessions (e.g., tmux)
bssh -C production --server-alive-interval 30 --server-alive-count-max 5 interactive

Interactive Mode Configuration

interactive:
 default_mode: multiplex # or single_node
 prompt_format: "[{node}] $ "
 history_file: ~/.bssh_history
 show_timestamps: true # Add timestamps to output
 work_dir: /home/user
 broadcast_prefix: "!all " # Custom prefix for broadcast commands
 node_switch_prefix: "!" # Custom prefix for special commands

clusters:
 production:
 interactive:
 default_mode: single_node # Different mode for this cluster
 prompt_format: "PROD> "
 work_dir: /var/app

[●くろまる ●くろまる ●くろまる] bssh> uptime
[node1] 10:23:45 up 5 days, 2:14, 1 user, load average: 0.15, 0.12, 0.09
[node2] 10:23:45 up 3 days, 4:22, 2 users, load average: 0.23, 0.19, 0.17
[node3] 10:23:45 up 7 days, 1:45, 1 user, load average: 0.08, 0.11, 0.10
[●くろまる ●くろまる ●くろまる] bssh> exit

Interactive Mode Special Commands

interactive:
 node_switch_prefix: "@" # Use @ instead of !
 broadcast_prefix: "@all " # Use @all instead of !broadcast

Node Indicators in Prompt

Example Interactive Session

$ bssh -C production interactive
Connected to 3 nodes
[●くろまる ●くろまる ●くろまる] bssh> !status
Active nodes: node1.example.com, node2.example.com, node3.example.com
[●くろまる ●くろまる ●くろまる] bssh> !node1
Switched to node 1
[●くろまる ○しろまる ○しろまる] (1/3) bssh> hostname
[node1] node1.example.com
[●くろまる ○しろまる ○しろまる] (1/3) bssh> !broadcast date
Broadcasting command to all connected nodes...
[node1] Thu Aug 22 10:30:00 UTC 2025
[node2] Thu Aug 22 10:30:00 UTC 2025
[node3] Thu Aug 22 10:30:00 UTC 2025
[●くろまる ○しろまる ○しろまる] (1/3) bssh> !all
All nodes activated
[●くろまる ●くろまる ●くろまる] bssh> df -h /
[node1] Filesystem Size Used Avail Use% Mounted on
[node1] /dev/sda1 20G 5.5G 14G 30% /
[node2] Filesystem Size Used Avail Use% Mounted on
[node2] /dev/sda1 20G 7.2G 12G 38% /
[node3] Filesystem Size Used Avail Use% Mounted on
[node3] /dev/sda1 20G 4.1G 15G 22% /
[●くろまる ●くろまる ●くろまる] bssh> exit
Goodbye!

Output File Management

File Structure

output-dir/
├── hostname1_20250821_143022.stdout # Standard output
├── hostname1_20250821_143022.stderr # Standard error (if any)
├── hostname2_20250821_143022.stdout # Per-node outputs
├── hostname2_20250821_143022.error # Connection/execution errors
├── hostname3_20250821_143022.empty # Marker for no output
└── summary_20250821_143022.txt # Overall execution summary

File Types

File Headers

# Command: df -h
# Host: server1.example.com
# User: admin
# Exit Status: 0
# Timestamp: 20250821_143022
[actual command output follows]

Example Usage

# Save outputs to timestamped directory
bssh -C production --output-dir ./results/$(date +%Y%m%d) "ps aux | head -10"
# Collect system information
bssh -C all-servers --output-dir ./system-info "uname -a; df -h; free -m"
# Debug failed services
bssh -C webservers --output-dir ./debug "systemctl status nginx"

Development

Building

cargo build

Testing

cargo test

Running locally

cargo run -- -H localhost "echo hello"

SSH Implementation

License

Changelog

Recent Updates