$n $1 the first parameter,$2 the second...
$# The number of command-line parameters.
$0 The name of current program.
$? Last command or function's return value.
$$ ...
单引号 ( '' )# grep Susan phonebook
Susan Goldberg 403-212-4921
Susan Topple 212-234-2343
如果我们想查找的是Susan Goldberg,不能直接使用grep Susan Goldberg phonebook命令,grep会把Goldberg和phonebook当作需要搜索的文件# grep 'Susan...
sdalog --helpUsage:sdalog -h/--help--time=timevalue[-f/--file]If you don't input 'time' option,it indicates you need all records of any time.Similarly, if you don't input 'type' option, it indicate...