我看到很多人这样做

autoload -Uz compinit

compinit

和其他人这样做

autoload -U compinit

compinit -i

我想知道这个区别.我应该使用哪一个？

解决方法

自动加载,从
man zshbuiltins：

The flags -z and -k mark the function to be autoloaded in native or ksh emulation,as if the option KSH_AUTOLOAD were unset or were set,respectively.

-U标志可以追溯到：autoload等效于功能-u,这相当于排版-f.简而言之,排版用于：

Set or display attributes and values for shell parameters.

当-f与-U组合使用时：

[The -f flag causes] The names refer to functions rather than parameters. … The -u and -U flags cause the function to be marked for autoloading; -U also causes alias expansion to be suppressed when the function is loaded.

compinit是compsys使用的完成初始化函数,“较新的”Z-Shell完成系统.详见man zshcompsys.

-i标志用于：

to make compinit silently ignore all insecure files and directories use the option -i

一般来说,您应该使用autoload -Uz,根据this interesting read.