zsh starts incredibly slowly

ZSH takes about a second and a half from creating a new terminal window to being ready. I'm pretty sure that the culprit is compinit.

I haven't been able to find good documentation on compinit, but it looks like it should be caching all of the necessary things in some file like .zcompdump.

Any tricks on speeding it up?

oh-my-zsh was taking about 1.5 seconds to start up on my laptop. I wrote up some of the steps I took to get that down to about 0.25 seconds.

Another kind soul summarized the steps required to integrate my changes into your copy of oh-my-zsh.

The biggest problem is that compinit was being called a whole bunch of extra times instead of just one time after the fpath was completely defined. I made those changes on my branch of oh-my-zsh on github. The changes have been discussed on github and they seem to be working well for a few people. Hopefully the changes will be merged into oh-my-zsh in the near future.

While ZSH has it's own fair-share of slowdowns, if you find the terminal window blank for a few moments before you see the Last Login: line, you are going to need to clear your log files to see speed improvements. This is still an issue as of OSX Lion and will need to be done every several months. Lame, I know.

The command is:

sudo rm -rf /private/var/log/asl/*.asl

Of course, you need to read this article beforehand and so you know exactly what is going on, because running anything that says sudo rm needs to be thought about. I only put this here because your use of ZSH proves your competence with the command line to start.

My biggest improvement has come from removing items from the plugin=() section. The 'github' and 'brew' plugins are very slow to load.

I also removed hub which I had aliased togitand that sped up the prompt as well.

I've been using '/usr/bin/time zsh -i -c exit' to record the startup times, however compinit doesn't appear to make a big enough difference for me.

It'd be great to hear what others are doing to speed it up.

In my case, NVM was making it slow.

Original code (at .bash_profile, .zshrc loads my bash_profile)

export NVM_DIR="$HOME/.nvm"
[ -s "$NVM_DIR/nvm.sh" ] && \. "$NVM_DIR/nvm.sh"  # This loads nvm
[ -s "$NVM_DIR/bash_completion" ] && \. "$NVM_DIR/bash_completion"  # This loads nvm bash_completion

I've changed it to:

export NVM_DIR="$HOME/.nvm"
#[ -s "$NVM_DIR/nvm.sh" ] && \. "$NVM_DIR/nvm.sh"  # This loads nvm
[ -s "$NVM_DIR/bash_completion" ] && \. "$NVM_DIR/bash_completion"  # This loads nvm bash_completion
alias nvm="unalias nvm; [ -s "$NVM_DIR/nvm.sh" ] && . "$NVM_DIR/nvm.sh"; nvm $@"

Added the alias (last line), so I will only load NVM when I try to use it. It decreased the load time from 1.5 to 0.2 seconds.

/usr/bin/time zsh -i -c exit #If you want to time yours