Hi All,
My zsh has become very slow after upgrading to Mac Big Sur OS.
It was nvm that was causing the issue. So I researched and found that nvm can be lazy loaded with the `--no-use` option.
However, even after using --no-use, it was still slow. The reason is a simple echo command to /dev/stdin. It is taking >5 seconds. Below are the lines that are causing the issue
```
[ "_$( . /dev/stdin yes 2> /dev/null <<'EOF'
[ $# -gt 0 ] && nvm_echo $1
EOF
)" = "_yes" ]
```
We noticed that even a very basic echo to /dev/stdin is taking more than 5 seconds. For example
```
time ((echo abc) | (. /dev/stdin))
/dev/stdin:1: command not found: abc
( ( echo abc; ) | ( . /dev/stdin; ); ) 0.00s user 0.00s system 0% cpu 5.087 total
```
This happens only with shell built-in echo and doesn't happen with /bin/echo.
We tried many options and a more detailed discussion can be found in the below github issue
Looking forward to your help. You can directly reply in the github thread. It will help others as well.
Thanks,
Anand