Linux account management command and file describes

Command: # useraddsunday — — > add user useradd-u720-g100-M-s/bin/bashsunday-M not establishing root-d specifies the root directory-s use of sell # passwdsunday — — > add to user password # usermod-Lsunday — — > lock account # usermod-Usunday — — > unlock account # usermod-e2008-08-08sunday – > settings account expiration time # groupadddebian — — > add group account # useradd-gdebiansunday — — > specified user belongs to group # usermod-gdebiansunday — — > modify user belongs to group # groupdeldebian — — > delete group file:/etc/shadow username: encrypt password (if * indicates that the account could not be logged in): the last modified time (1970, 1, number of days): password in twice to modify the minimum number of days between: password change prior to warn the user of the number of days after the termination of the account: password is disabled by the number of days: 1, 1970, the date the account is disabled by the number of days: reserved domain drobbins: $ 1 $ 1234567890123456789012345678901: 11664: 0:-1:-1:-1:-1: 0 in/etc/passwdusername: password: UserID: GroupID: comment: homedirectory: sell user logon command to execute after/etc/groupgroupname: x (expressed in/etc/shadow qunzu password): GID: usernamesroot: x:0: root, sunday, onlyisi