Usage of Linuxdate

Linuxdate usage tips #! /Bin/bashecho-e & quot; iwillusetouchcommandtocreate3files & quot; read-p & quot; inputfilename: & quot; fileuserfilename $ {fileuser:-& quot; f Linux date usage tips #! /Bin/bashecho-e "I will use touch command to create 3 files" read-p "input filename:" fileuserfilename =$ {fileuser: -"filename"} date1 = $ (date -- date = '2 days ago '+ % Y % m % d) date2 = $ (date -- date = '1 days ago '+ % Y % m % d) date3 = $ (date + % Y % m % d) file1 =$ {filename }$ {date1} file2 =2 {filename }$ {date2} file3 =3 {filename }$ {date3} touch "$ file1" touch "$ file2" the shell script above touch "$ file3" ls was used two days ago, one day ago, we joined the current date and the name entered by the user to create three files. . Filename =$ {fileuser:-"filename"} is used to determine whether the fileuser variable is null. if it is null, use filename instead. Date -- date = '2 days ago '+ % Y % m % d indicates that the date displayed two days ago is January 1, 20130908. if you want to represent the date of today, in this way, date = $ (date + % Y % m % d). If you want the expression, you can use % F, that is, date2 = $ (date -- date = '1 days ago '+ % F). This % F is equal to % Y-% m-% d, this is also acceptable, but it is too cumbersome. 1 days ago can also be changed to 1 months ago or 1 yeas ago. it must be noted that the later ++ must not be omitted.