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Tips & Extras (Read This Early, Save Pain Later)

These are the “small things” most courses skip, but they make you faster, safer, and way more comfortable in the terminal.

This repo is Bash-focused for scripting, but it’s totally normal to use Zsh as your daily interactive shell because it’s modern, customizable, and looks cool.

Quick idea

  • Use Zsh for your daily terminal experience.
  • Write scripts with a shebang like #!/usr/bin/env bash so they run in Bash consistently.

1) Bash vs Zsh (what you should actually do)

Why people use Zsh

People often use Zsh because:

  • it’s highly customizable (themes, plugins, prompt styles)
  • the interactive experience is smoother (autocomplete, suggestions, etc.)
  • it supports most things Bash users do day-to-day

Reality check (important)

  • Most Bash scripts work in Zsh only if you run them with Bash.
  • Zsh is not “Bash with skins”—it has differences.
  • That’s why scripts should specify the interpreter using a shebang.

Best workflow:

  • Interactive shell: Zsh
  • Script interpreter: Bash (via shebang)

2) “Which shell am I using?” (check when in doubt)

If you’re ever unsure what shell you (or your friend) is using:

echo "$SHELL"

More accurate for the current session:

ps -p $$ -o comm=

$SHELL often shows your default login shell. The ps ... $$ command tells you what’s running right now.

3) Learn these early: man, --help, tldr (lifesavers)

These three tools save you from guessing commands:

man ls
ls --help
tldr tar

Install tldr on Debian/Kali/Ubuntu:

sudo apt update
sudo apt install -y tldr

What they mean

  • man <command>: full manual (detailed)
  • <command> --help: quick built-in usage summary
  • tldr <command>: practical examples (fastest when you’re learning)

You’ll thank yourself later.

4) Quote variables by default (safe habit = fewer weird bugs)

A huge beginner trap is unquoted variables.

Bad:

rm -r $dir

Good:

rm -r -- "$dir"

Why it matters

  • filenames can contain spaces
  • empty variables can cause dangerous behavior
  • quoting makes scripts predictable and safer

5) Use ShellCheck (your Bash “spellchecker”)

ShellCheck catches bugs and bad practices before you run a script.

Install:

sudo apt install -y shellcheck

Use:

shellcheck script.sh

In real sensitive environment, it might save you from a catastrophe.

6) Make a safe practice playground folder

Beginners sometimes run destructive commands in the wrong directory.

Make a safe playground:

mkdir -p ~/playground/shell
cd ~/playground/shell

Now experiment there first, not in random system folders.

7) Understand PATH (why a command runs / doesn’t run)

When you see “command not found” or “wrong version”, it’s often PATH.

Check:

echo "$PATH"
which bash
type -a python

if it is still not working, you can start an AI Assistant troubleshooting session from there, and fix that problem easily.

8) Use history like a power user

Search your command history:

  • Ctrl + R → reverse search (type a few letters)

Show recent commands:

history | tail -n 20

Why it matters

  • massive speed boost
  • reduces mistakes from retyping long commands

9) Customize your shell config (~/.bashrc, ~/.zshrc) — life changer

Your shell config file controls:

  • aliases (alias ll='ls -la')
  • prompt style
  • keybindings
  • environment variables
  • plugins (especially in Zsh)

Common files:

  • ~/.bashrc → Bash config (interactive)
  • ~/.zshrc → Zsh config (interactive)

you should find a guide on this also in this repo, I should share a template and also teach you how to customize it.

Pro move: back up your config on GitHub

Make a private repo (or public if you’re comfortable) for your dotfiles:

  • dotfiles repository idea:
    • .zshrc
    • .bashrc
    • .gitconfig
    • terminal theme exports (optional)

Why it matters

  • you can restore your setup instantly after reinstall
  • you can quickly load your setup on another machine
  • helps you build a consistent workflow everywhere

Safety note: never upload secrets (API keys, tokens, passwords). If unsure, don’t push it, review first.

10) “If Zsh causes issues, can I switch back to Bash easily?”

Yes.

Run Bash for just one session (temporary)

bash

Exit back to Zsh:

exit

Change your default shell back to Bash (Linux)

chsh -s "$(which bash)"

Change to Zsh:

chsh -s "$(which zsh)"

You may need to log out and log back in for the default shell change to take effect.

11) About shebangs (important: what they do and what they don’t)

A shebang like this:

#!/usr/bin/env bash

…tells the OS: “run this script using Bash”.

So do we always need to type bash script.sh?

No — if:

  • the script has a shebang,
  • it has execute permission (chmod +x script.sh),
  • and you run it like ./script.sh.

Example:

chmod +x script.sh
./script.sh

What shebang does NOT do

  • It does not change your interactive shell.
    • You can be using Zsh interactively and still run Bash scripts perfectly.

That’s exactly why using Zsh + Bash-shebang scripts is a clean combo.

One rule to keep you safe

If you don’t understand a command, don’t run it as sudo yet. Learn what it does first (use man, --help, tldr).

Optional: “Ricing” your terminal (Zsh + Oh My Zsh + Powerlevel10k)

If you’re going to spend a lot of time in the terminal, making it look clean and feel comfortable is a real productivity win and if you are too lazy to do it, you can use an installer I made exactly for people like you! Click here to get there: https://github.com/UnExplainableFish52/pvtcfg

Easy ricing in under a minute! No Cap!!

This section (Manual Ricing) is optional (you can skip it and still follow the whole course), but if you do it, your daily terminal experience becomes way nicer.

We’ll set up:

  • Zsh (Z Shell) as your interactive shell
  • Oh My Zsh for managing Zsh config/plugins/themes easily
  • Powerlevel10k for a modern, fast prompt
  • Nerd Font so icons/symbols render properly
  • Two useful plugins:
    • zsh-autosuggestions (suggests commands as you type)
    • zsh-syntax-highlighting (color highlights commands; helps catch mistakes)

Optional video (sleek inspiration): https://youtu.be/DmpMgTL6R9A?si=IWOcNPoytzeDJ0qt Not required if you follow the steps below.

Step 0) Install Zsh (Kali/Debian/Ubuntu)

sudo apt update
sudo apt install -y zsh git curl
zsh --version

Make Zsh your default shell (recommended if you want the full experience):

chsh -s "$(which zsh)"

You may need to log out and log back in (or restart your terminal) for this to apply.

Step 1) Install Oh My Zsh

Official repo: https://github.com/ohmyzsh/ohmyzsh

Install (curl):

sh -c "$(curl -fsSL https://raw.githubusercontent.com/ohmyzsh/ohmyzsh/master/tools/install.sh)"

After install, you’ll have:

  • ~/.zshrc (your Zsh config)
  • ~/.oh-my-zsh/ (Oh My Zsh directory)

Small tip: you do not need to be inside a special config folder before running these commands. Run them from your normal home workspace, and the relative paths in the clone commands will place everything in the right location automatically.

Step 2) Install Powerlevel10k theme

Official repo: https://github.com/romkatv/powerlevel10k

git clone --depth=1 https://github.com/romkatv/powerlevel10k.git \
  "${ZSH_CUSTOM:-$HOME/.oh-my-zsh/custom}/themes/powerlevel10k"

Enable it in ~/.zshrc:

nano ~/.zshrc

Find:

ZSH_THEME="..."

Replace with:

ZSH_THEME="powerlevel10k/powerlevel10k"

Reload:

source ~/.zshrc

If it’s set up correctly, you’ll usually see the Powerlevel10k wizard. If not, run it manually:

p10k configure

Step 3) Install a Nerd Font (so icons don’t look broken)

Powerlevel10k looks best with a Nerd Font. Without it you may see squares or weird symbols.

Recommended: MesloLGS NF (commonly used with Powerlevel10k)

Quick install helper (downloads fonts to your home directory):

mkdir -p ~/.local/share/fonts
cd ~/.local/share/fonts
wget -q https://github.com/romkatv/powerlevel10k-media/raw/master/MesloLGS%20NF%20Regular.ttf
wget -q https://github.com/romkatv/powerlevel10k-media/raw/master/MesloLGS%20NF%20Bold.ttf
wget -q https://github.com/romkatv/powerlevel10k-media/raw/master/MesloLGS%20NF%20Italic.ttf
wget -q https://github.com/romkatv/powerlevel10k-media/raw/master/MesloLGS%20NF%20Bold%20Italic.ttf
fc-cache -fv

Now go to your terminal settings and select MesloLGS NF as the font, then restart the terminal.

Font setting is done in your terminal app (not inside Bash/Zsh).

Step 4) Install plugins (autosuggestions + syntax highlighting)

4.1) zsh-autosuggestions

Repo: https://github.com/zsh-users/zsh-autosuggestions

git clone https://github.com/zsh-users/zsh-autosuggestions \
  ${ZSH_CUSTOM:-~/.oh-my-zsh/custom}/plugins/zsh-autosuggestions

4.2) zsh-syntax-highlighting

Repo: https://github.com/zsh-users/zsh-syntax-highlighting

git clone https://github.com/zsh-users/zsh-syntax-highlighting.git \
  ${ZSH_CUSTOM:-~/.oh-my-zsh/custom}/plugins/zsh-syntax-highlighting

Enable plugins in ~/.zshrc

Open:

nano ~/.zshrc

Find the plugins line:

plugins=(git)

Change it to (make sure syntax-highlighting is last):

plugins=(git zsh-autosuggestions zsh-syntax-highlighting)

Reload:

source ~/.zshrc

Troubleshooting (fast fixes)

1) Theme not applying

  • Confirm ~/.zshrc contains: 
    ZSH_THEME="powerlevel10k/powerlevel10k"
  • Then: 
    source ~/.zshrc

2) Icons look broken

  • Your font is not set to a Nerd Font in terminal settings.
  • Set it to MesloLGS NF, restart terminal.

3) p10k: command not found

  • Powerlevel10k isn’t loaded; re-check the theme line in ~/.zshrc.

How to revert (important)

If you ever want to undo this setup:

Revert 1) Switch back to Bash temporarily (one terminal session)

bash

Back to Zsh:

exit

Revert 2) Change default shell back to Bash

chsh -s "$(which bash)"

Log out and log back in.

Revert 3) Disable Powerlevel10k theme

Edit:

nano ~/.zshrc

Change:

ZSH_THEME="powerlevel10k/powerlevel10k"

To something simple like:

ZSH_THEME="robbyrussell"

Reload:

source ~/.zshrc

Revert 4) Disable plugins

Edit the plugins line back to:

plugins=(git)

Reload:

source ~/.zshrc

Revert 5) Uninstall Oh My Zsh (full removal)

Oh My Zsh usually provides an uninstall script:

uninstall_oh_my_zsh

If that command isn’t found, remove the folder manually (careful):

rm -rf ~/.oh-my-zsh

Then you can remove OMZ-related lines from ~/.zshrc or restore a backup.