grep -rn "helloword" *
[grep] 命令
[-r] : -r 是递归查找
[-n] : -n 是显示行号
["helloworld"] : 要查找的字符串
[*] : * 表示当前目录下的所有文件，也可以指定为某个文件名
curl
--header "Authorization: 123"
mdfind
mdfind -name .pdf | grep -vE '(System|Library|anaconda3|Application|AutoCAD|usr)'
find
find / -name '*pdf' | grep -vE '(System|Library|anaconda|Application|AutoCAD|usr|DocumentRevisions)' | wc -l
Options
-V, --version
Display version information and exit.
-v, --invert(reverse)-match
Selected lines are those not matching any of the specified patterns.
-E, --extended-regexp
Interpret pattern as an extended regular expression (i.e. force grep to behave as egrep).
