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Zsh Terminal Differentiation: Managing Multiple SSH Sessions Without Losing Your Mind

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Zsh Terminal Differentiation: Managing Multiple SSH Sessions Without Losing Your Mind

Stop Getting Lost in Multiple SSH Sessions - Use Color-Coded Zsh Prompts!

The Problem

Picture this: You’re managing a cybersecurity lab with 4 different servers. You have terminal windows open for your red team attack server, blue team SIEM, target server, and your local Mac. They all have identical bash prompts:

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ubuntu@vps-008e89ad:~$
ubuntu@vps-008e89ad:~$
ec2-user@ip-172-31-18-130:~$
(base) ➜  ~

Which server am I on right now? 🤔

You type sudo rm -rf /var/log/* and hit enter… then realize you just deleted logs on the WRONG SERVER. 😱

The Solution: Color-Coded Zsh Prompts

I solved this problem by:

  1. Installing zsh (Z shell) on all my servers
  2. Adding color-coded prompts with emojis for instant visual identification
  3. Enabling zsh-autosuggestions for ghost text command completion
  4. Changing server hostnames to match their roles

Now my terminals look like this:

  • 🎖️ Mac Command Center: (base) 🎖️ COMMAND ~ ➜
  • 🔴 Red Team Attack: 🔴 RED-TEAM ~ ➜
  • 🔵 Blue Team SIEM: 🔵 BLUE-SIEM ~ ➜
  • 🎯 Target Server: 🎯 TARGET-AWS ~ ➜

Instant visual identification! No more confusion, no more mistakes.

What is Zsh?

Zsh (Z Shell) is an extended version of the Bourne Shell (bash) with tons of improvements:

  • Better tab completion
  • Command history sharing
  • Spelling correction
  • Theme and plugin support
  • Autosuggestions - shows ghost text of previous commands as you type

It’s the default shell on macOS (since Catalina), and it’s perfect for power users managing multiple servers.

Installation Guide

Ubuntu Servers (Contabo, OVH, DigitalOcean, etc.)

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# Update package list
sudo apt update

# Install zsh and plugins
sudo apt install -y zsh zsh-autosuggestions zsh-syntax-highlighting

# Verify installation
which zsh
# Output: /usr/bin/zsh

# Check version
zsh --version
# Output: zsh 5.9 (or similar)

Amazon Linux (AWS EC2)

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# Amazon Linux uses yum, not apt!
sudo yum install -y zsh

# Verify installation
which zsh
# Output: /usr/bin/zsh

# Note: zsh-autosuggestions and syntax-highlighting
# aren't in default repos, need manual installation (see below)

Setting Up Color-Coded Prompts

Red Team Attack Server (Contabo)

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# Create .zshrc configuration
cat >> ~/.zshrc << 'EOF'
# Red Team Prompt Configuration
PROMPT='%F{red}🔴 RED-TEAM%f %F{cyan}%~%f %F{red}➜%f '

# Enable autosuggestions (Ubuntu only)
source /usr/share/zsh-autosuggestions/zsh-autosuggestions.zsh

# Enable syntax highlighting (Ubuntu only)
source /usr/share/zsh-syntax-highlighting/zsh-syntax-highlighting.zsh
EOF

# Switch to zsh
zsh

Blue Team SIEM Server (OVH Bravo)

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# Create .zshrc configuration
cat >> ~/.zshrc << 'EOF'
# Blue Team SIEM Prompt Configuration
PROMPT='%F{blue}🔵 BLUE-SIEM%f %F{cyan}%~%f %F{blue}➜%f '

# Enable autosuggestions (Ubuntu only)
source /usr/share/zsh-autosuggestions/zsh-autosuggestions.zsh

# Enable syntax highlighting (Ubuntu only)
source /usr/share/zsh-syntax-highlighting/zsh-syntax-highlighting.zsh
EOF

# Switch to zsh
zsh

Target Server (AWS EC2)

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# Create .zshrc configuration
cat >> ~/.zshrc << 'EOF'
# Target Server Prompt Configuration
PROMPT='%F{cyan}🎯 TARGET-AWS%f %F{cyan}%~%f %F{cyan}➜%f '
EOF

# Switch to zsh
zsh

Understanding the Prompt Format

Let me break down the zsh prompt syntax:

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PROMPT='%F{red}🔴 RED-TEAM%f %F{cyan}%~%f %F{red}➜%f '
  • %F{red} - Start red color
  • 🔴 RED-TEAM - Emoji and text
  • %f - End color (reset to default)
  • %F{cyan} - Start cyan color
  • %~ - Current directory (with ~ for home)
  • %f - End color
  • %F{red}➜%f - Red arrow symbol
  • Space at end - cursor position

Available colors:

  • red, green, blue, cyan, magenta, yellow, white, black

Useful prompt codes:

  • %~ - Current directory (with ~ for home)
  • %/ - Full current directory path
  • %n - Username
  • %m - Hostname
  • %D - Date
  • %T - Time (24-hour format)

The Magic of Zsh Autosuggestions 👻

This is the killer feature that makes zsh worth it!

As you type commands, zsh shows ghost text (greyed out) of previous commands you’ve run:

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# You type: curl
# Zsh shows: curl http://100.77.2.103:9200/_cat/indices?v

# Press → (right arrow) to accept the suggestion!

How it works:

  • Zsh remembers your command history
  • As you type, it matches against previous commands
  • Shows the completion in grey text
  • Press → (right arrow) to accept
  • Press → End to accept and move to end of line
  • Keep typing to ignore the suggestion

This saves SO MUCH TIME when running repeated commands with long parameters!

Changing Server Hostnames

Want your server’s actual hostname to match the role? Here’s how:

Red Team Server (Contabo)

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# Set new hostname
sudo hostnamectl set-hostname red-team

# Update /etc/hosts (replace old hostname)
sudo sed -i 's/vps-008e89ad/red-team/g' /etc/hosts

# Verify the change
hostnamectl

# Apply immediately without reboot
exec bash
zsh

Blue Team SIEM (OVH)

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# Set new hostname
sudo hostnamectl set-hostname blue-siem

# Update /etc/hosts
sudo sed -i 's/vps-e87f8afd/blue-siem/g' /etc/hosts

# Verify
hostnamectl

# Apply immediately
exec bash
zsh

AWS EC2 Target

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# Set new hostname
sudo hostnamectl set-hostname target-aws

# Update /etc/hosts
sudo sed -i 's/ip-172-31-18-130/target-aws/g' /etc/hosts

# Verify
hostnamectl

# Apply immediately
exec bash
zsh

Now when you SSH in, you’ll see:

  • ubuntu@red-team:~$ (before zsh)
  • 🔴 RED-TEAM ~ ➜ (after zsh)

Making Zsh Your Default Shell

Want zsh to load automatically when you SSH in?

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# Make zsh your default shell
chsh -s $(which zsh)

# Verify
echo $SHELL
# Output: /usr/bin/zsh

# Next login will automatically use zsh!

Note: You might need to log out and back in for this to take effect.

Installing Zsh Autosuggestions on Amazon Linux (Manual Method)

Amazon Linux doesn’t have zsh-autosuggestions in default repos. Here’s how to install it manually:

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# Clone the repository
git clone https://github.com/zsh-users/zsh-autosuggestions ~/.zsh/zsh-autosuggestions

# Add to .zshrc
echo "source ~/.zsh/zsh-autosuggestions/zsh-autosuggestions.zsh" >> ~/.zshrc

# Reload configuration
source ~/.zshrc

Bonus: Syntax Highlighting

Zsh-syntax-highlighting makes your commands colorful:

  • ✅ Green = valid command
  • ❌ Red = invalid command/typo
  • 🔵 Blue = existing file/directory
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# Ubuntu installation
sudo apt install -y zsh-syntax-highlighting
echo "source /usr/share/zsh-syntax-highlighting/zsh-syntax-highlighting.zsh" >> ~/.zshrc

# Amazon Linux (manual)
git clone https://github.com/zsh-users/zsh-syntax-highlighting.git ~/.zsh/zsh-syntax-highlighting
echo "source ~/.zsh/zsh-syntax-highlighting/zsh-syntax-highlighting.zsh" >> ~/.zshrc

# Reload
source ~/.zshrc

Troubleshooting

Problem: Colors not showing up

Solution: Make sure your terminal supports 256 colors:

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echo $TERM
# Should show: xterm-256color or similar

# If not, add to .zshrc:
export TERM=xterm-256color

Problem: Emojis showing as boxes

Solution: Your terminal needs Unicode support. Try:

  • macOS Terminal: Works by default
  • iTerm2: Works perfectly
  • Windows Terminal: Works great
  • PuTTY: Enable UTF-8 in settings

Problem: Autosuggestions not working

Solution: Check if the plugin is loaded:

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# Test if plugin exists
ls /usr/share/zsh-autosuggestions/

# If missing, reinstall
sudo apt install -y zsh-autosuggestions

# Make sure .zshrc has the source line
cat ~/.zshrc | grep autosuggestions

Problem: “command not found” after switching to zsh

Solution: Your PATH might not be set correctly. Add to ~/.zshrc:

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# Set PATH
export PATH=$PATH:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin

My Complete .zshrc Configuration

Here’s my production .zshrc for the red team server:

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# Red Team Prompt Configuration
PROMPT='%F{red}🔴 RED-TEAM%f %F{cyan}%~%f %F{red}➜%f '

# Enable 256 colors
export TERM=xterm-256color

# Autosuggestions plugin
source /usr/share/zsh-autosuggestions/zsh-autosuggestions.zsh

# Syntax highlighting plugin
source /usr/share/zsh-syntax-highlighting/zsh-syntax-highlighting.zsh

# Command history
HISTFILE=~/.zsh_history
HISTSIZE=10000
SAVEHIST=10000
setopt SHARE_HISTORY

# Enable completion
autoload -Uz compinit
compinit

# Case-insensitive completion
zstyle ':completion:*' matcher-list 'm:{a-z}={A-Za-z}'

# Aliases
alias ll='ls -lah'
alias ..='cd ..'
alias ...='cd ../..'

Before and After Comparison

Before (all servers with bash):

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ubuntu@vps-008e89ad:~$
ubuntu@vps-e87f8afd:~$
ec2-user@ip-172-31-18-130:~$
(base) ➜  ~

After (with color-coded zsh):

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🔴 RED-TEAM ~ ➜
🔵 BLUE-SIEM ~ ➜
🎯 TARGET-AWS ~ ➜
🎖️ COMMAND ~ ➜

Key Takeaways

  1. Visual differentiation prevents mistakes - Color-coded prompts with emojis make it instantly obvious which server you’re on
  2. Zsh autosuggestions save massive time - Ghost text completion of previous commands is a game-changer
  3. Ubuntu uses apt, Amazon Linux uses yum - Don’t mix up your package managers!
  4. Hostname changes require /etc/hosts update - Don’t forget to update both files
  5. Syntax highlighting catches typos - See invalid commands in red before you run them
  6. Make it your default shell - Use chsh -s $(which zsh) for automatic loading

Use Cases

This setup is perfect for:

  • 🔐 Penetration testers managing red team/blue team infrastructure
  • ☁️ DevOps engineers managing multiple cloud servers
  • 🛡️ Security analysts running SIEM and monitoring systems
  • 💻 System administrators managing production/staging/development environments
  • 🎓 Students working on cybersecurity assignments (like my NCI Master’s!)

Next Steps

After setting up zsh, you might want to explore:

  • Oh My Zsh - Framework for managing zsh configuration (themes and plugins)
  • Powerlevel10k - Advanced prompt theme with Git integration
  • Zsh-completions - Additional command completions
  • Aliases - Custom shortcuts for frequently-used commands

Tools Used

  • zsh - Z Shell (extended Bourne shell)
  • zsh-autosuggestions - Ghost text command completion
  • zsh-syntax-highlighting - Colorful command syntax
  • hostnamectl - Systemd hostname control

Final Thoughts

Terminal differentiation might seem like a small thing, but when you’re managing multiple servers for cybersecurity testing, it’s essential for preventing mistakes.

The combination of color-coded prompts, emojis, and zsh autosuggestions transforms terminal management from confusing to delightful. I can now glance at any terminal window and instantly know which server I’m on.

Total setup time: 5 minutes per server Mistakes prevented: Countless Productivity boost: Massive

If you manage more than 2 servers, do yourself a favor and set this up today. Your future self will thank you!

Managing multiple servers doesn’t have to be confusing.

Rangers lead the way! 🎖️

Quick Reference Card

Server TypeHostnamePromptColorEmoji
Command Centercommand🎖️ COMMAND ~ ➜Default🎖️
Red Teamred-team🔴 RED-TEAM ~ ➜Red🔴
Blue Teamblue-siem🔵 BLUE-SIEM ~ ➜Blue🔵
Targettarget-aws🎯 TARGET-AWS ~ ➜Cyan🎯

Ubuntu Install: sudo apt install -y zsh zsh-autosuggestions zsh-syntax-highlighting Amazon Linux Install: sudo yum install -y zsh Set Hostname: sudo hostnamectl set-hostname <name> Make Default: chsh -s $(which zsh)

Copy, paste, customize, and never get confused again! 🚀

linux, terminal, productivity
zsh ssh terminal autosuggestions ubuntu amazon-linux devops sysadmin
This post is licensed under CC BY 4.0 by the author.