Shell Speedup
https://work.lisk.in/2020/11/20/even-faster-bash-startup.html#completions
https://danpker.com/posts/faster-bash-startup/
Benchmark bash startup speed by hyperfine
hyperfine 'bash -i'
Benchmark 1: bash -i Time (mean ± σ): 262.5 ms ± 29.4 ms [User: 156.9 ms, System: 74.1 ms] Range (min … max): 249.0 ms … 345.9 ms 10 runs
$ source ~/.bash_profile
bash_exports: 0.015
bash_aliases: 0.000
bash_autocompletion: 0.000
bash_colors: 0.000
bash_functions: 0.000
bash_options: 0.000
bash_prompt: 0.024
bash.local: 0.000
conda: 0.000
Benchmark 1: bash --login
Time (mean ± σ): 45.8 ms ± 2.0 ms [User: 16.3 ms, System: 20.7 ms]
Range (min … max): 42.0 ms … 52.8 ms 57 runs
eval $(/opt/homebrew/bin/brew shellenv) would add ~ 27 ms delay
bash_prompt add ~ 20 ms
bash_exports: 0.001 s
bash_aliases: 0.000 s
bash_autocompletion: 0.029 s
bash_colors: 0.000 s
bash_functions: 0.000 s
bash_options: 0.000 s
bash_prompt: 0.022 s
bash.local: 0.000 s
conda: 0.003
Autocompletion diff: 140 ms on load up
myMacbook:~ wyq977$ hyperfine 'bash --login'
Benchmark 1: bash --login
Time (mean ± σ): 12.9 ms ± 0.8 ms [User: 5.0 ms, System: 4.9 ms]
Range (min … max): 11.7 ms … 16.8 ms 187 runs
myMacbook:~ wyq977$ hyperfine 'bash -i'
Benchmark 1: bash -i
Time (mean ± σ): 160.2 ms ± 2.4 ms [User: 120.7 ms, System: 33.2 ms]
Range (min … max): 157.3 ms … 164.9 ms 17 runs
ZSH is much faster?
myMacbook:~ wyq977$ hyperfine 'zsh --login'
Benchmark 1: zsh --login
Time (mean ± σ): 4.4 ms ± 0.6 ms [User: 1.3 ms, System: 1.8 ms]
Range (min … max): 3.2 ms … 7.2 ms 311 runs
❯ hyperfine 'zsh -cli exit'
Benchmark 1: zsh -cli exit
Time (mean ± σ): 72.8 ms ± 1.5 ms [User: 26.2 ms, System: 30.2 ms]
Range (min … max): 69.7 ms … 76.5 ms 39 runs
❯ hyperfine '/opt/homebrew/bin/bash -cli exit'
Benchmark 1: /opt/homebrew/bin/bash -cli exit
Time (mean ± σ): 77.0 ms ± 3.4 ms [User: 37.4 ms, System: 27.3 ms]
Range (min … max): 73.9 ms … 93.6 ms 31 runs