Okay, absolutely. Adding a cleanup step is a great idea to keep things tidy. I'll add a "Step 5" to the blog post draft.
Is opening a new terminal window or tab feeling sluggish? Do you tap your fingers waiting for your Zsh prompt to appear? If you're using popular tools like NVM (Node Version Manager) and Autojump on macOS, they might be the culprits behind that frustrating delay.
Recently, I noticed my own Zsh startup taking several seconds. After some investigation, the primary offenders were NVM's initialization script and, surprisingly, Autojump's sourcing process. The good news? There are blazing-fast, modern alternatives written in Rust: FNM (Fast Node Manager) and Zoxide.
This post will guide you through diagnosing your Zsh startup time and replacing NVM and Autojump with their speedier counterparts. Let's reclaim those lost seconds!
Step 1: Diagnose the Delay (Confirming the Culprits)
Before replacing anything, let's confirm what's slow. While Zsh's built-in zprof is useful for profiling Zsh functions, it sometimes doesn't accurately capture time spent running external commands or sourcing external scripts during startup. We'll use the simple time command:
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Baseline Zsh Time: How fast does Zsh start without your config?
time zsh -f -i -c exit
(-f skips .zshrc, -i simulates interactive, -c exit exits immediately). Expect this to be very fast (e.g., ~0.1 seconds).
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Time Potential Offenders: Check the initialization time of suspects like NVM and Autojump. (Replace paths with your actual ones).
# Time NVM init (if you were using it) - find the source line in your .zshrc
# Example: time zsh -f -c '[ -s "$HOME/.nvm/nvm.sh" ] && . "$HOME/.nvm/nvm.sh"'
# Time Autojump init (find the source line in your .zshrc)
# Common paths: ~/.local/share/autojump/autojump.sh or ~/Library/autojump/autojump.sh
# Or the one often installed by Homebrew: /usr/local/etc/profile.d/autojump.sh or /opt/homebrew/etc/profile.d/autojump.sh
time zsh -f -c '[ -f /path/to/your/autojump.sh ] && . /path/to/your/autojump.sh'
In my case, the Autojump sourcing took over 2 seconds, and NVM (before I removed it) was also notoriously slow. If you see significant times here (anything over a few tenths of a second adds up), replacing them is worthwhile.
Step 2: Replace NVM with FNM
FNM is significantly faster than the shell-script-based NVM.
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Remove NVM Config: Open your ~/.zshrc file. Find and delete or comment out the lines that load NVM. They typically look like:
# Example lines to remove:
# export NVM_DIR="$HOME/.nvm"
# [ -s "$NVM_DIR/nvm.sh" ] && \. "$NVM_DIR/nvm.sh"
# [ -s "$NVM_DIR/bash_completion" ] && \. "$NVM_DIR/bash_completion"
# Or lines sourcing from /usr/local/opt/nvm or /opt/homebrew/opt/nvm
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Install FNM: The easiest way on macOS is via Homebrew:
brew install fnm
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Configure FNM: Add the following line to the end of your ~/.zshrc:
# Add this for FNM initialization
eval "$(fnm env --use-on-cd)"
--use-on-cd: This magic flag tells FNM to automatically switch Node versions when you cd into a directory containing a .nvmrc or .node-version file.
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Restart Your Shell: Close and reopen your terminal, or run source ~/.zshrc.
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Install Node Versions: FNM manages its own installs.
- Install latest LTS:
fnm install --lts
- Install specific version:
fnm install 18
- List installed:
fnm ls
- Set default:
fnm default <version> (e.g., fnm default lts)
- Use in current shell:
fnm use <version>
Step 3: Replace Autojump with Zoxide
Zoxide is a super-fast reimplementation of autojump/z/fasd.
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Remove Autojump Config: Open your ~/.zshrc. Find and delete or comment out the line that sources autojump.sh. It looks like:
# Example line to remove:
# [ -f /path/to/your/autojump.sh ] && . /path/to/your/autojump.sh
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Install Zoxide: Again, Homebrew is simple:
brew install zoxide
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Configure Zoxide: Add the following line to the end of your ~/.zshrc:
# Add this for Zoxide initialization
eval "$(zoxide init zsh)"
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Understand the Command Change: Zoxide uses z by default, not j.
- To jump:
z part_of_dir_name (e.g., z project)
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(Optional) Keep Using j: If you prefer j, modify the init line:
# Use 'j' instead of 'z' for Zoxide
eval "$(zoxide init zsh --cmd j)"
Restart your shell after changing this.
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Import Autojump History: Don't lose your navigation history!
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Find your autojump.txt file. Common locations are ~/.local/share/autojump/autojump.txt or (as in my case) ~/Library/autojump/autojump.txt. Use ls or find ~ -name autojump.txt to locate yours.
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Run the import command (replace the path with your actual path):
zoxide import --from autojump /path/to/your/autojump.txt
Example: zoxide import --from autojump ~/Library/autojump/autojump.txt
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Restart Your Shell: Close and reopen your terminal, or run source ~/.zshrc.
Step 4: Enjoy the Speed!
Now, open a new terminal tab or window. You should feel a significant difference – that multi-second delay should be gone, replaced by a near-instantaneous prompt!
You can even run time zsh -i -c exit again (note: this won't load .zshrc, so it tests the core Zsh plus anything in global configs; simply opening a new tab is the best "feel" test) to measure the difference, though the real proof is the absence of that annoying wait.
Step 5: Clean Up Old Files (Optional but Recommended)
Once you are completely confident that FNM and Zoxide are working correctly and you've imported your data, you can remove the old files and directories to free up space and prevent potential future conflicts.
Warning: The rm -rf command permanently deletes files and directories. Double-check the paths carefully before running these commands!
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Remove NVM Directory: This directory contains all the Node versions NVM managed.
# Double-check this is the correct path for your NVM installation!
rm -rf ~/.nvm
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Remove Autojump Data Directory: This contains the old database and any other files Autojump used. Check which location yours was in (from Step 3, part 6).
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If it was in ~/.local/share/autojump:
rm -rf ~/.local/share/autojump
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If it was in ~/Library/autojump:
rm -rf ~/Library/autojump
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(If it was somewhere else, adjust the path accordingly)
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(Optional) Remove via Homebrew: If you originally installed NVM or Autojump using Homebrew and don't need the Homebrew package entry anymore, you can also uninstall them via Homebrew. Note: This usually won't remove the data directories (~/.nvm, ~/Library/autojump, etc.) which is why the rm -rf commands above are still necessary for a full cleanup.
# brew uninstall nvm
# brew uninstall autojump
Performing this cleanup step isn't strictly necessary for speed, but it keeps your home directory tidy and avoids potential confusion down the line.
By swapping out older, script-based tools for their faster, compiled counterparts, you can make your Zsh experience much smoother. Happy (and faster) navigating!
