2020-09

ユーザーの設定を変更するユーザーには予め、UIDやGID、ホームディレクトリなどが指定されている。これらの情報を後から変...

ユーザーを削除するユーザーを削除するコマンドはuserdel。このコマンドを実行すると、ユーザー情報は削除されるが、ユー...

一般ユーザーでroot権限のコマンドを実行する一般ユーザーでログインの時、root権限のコマンドを使用する場合は、sud...

他のユーザにファイルを見せないようにするLinuxでは、他のユーザにファイルを見せないようにすることができる。chmod...

To create and add a new user, use the "useradd" commandBy specifying a user name as an argument to the command, a user will be created. The user directory will be created under the /home directory, and the group name will be the same as the user name.

To create and add a new group, use the "groupadd" command.Information about groups is described in /etc/group and can be edited, but it is better to edit the group information with the vigr command instead of directly editing the "/etc/group" file.

Check the group in /etc/passwd and /etc/group (check the gid)Users always belong to a group, and the group described in the /etc/passwd and /etc/group files is the primary group.The gid (group ID) is stored in the /etc/passwd and /etc/group files

Group information in Linux is stored in the "/etc/group" file, which has the following notationtama:x:500:From left to right, tama is the group name, X is the password (when it says X, it is written in the /etc/gshadow file). 500 is the GID.To make a user belong to multiple groups, edit the "/etc/group" file, but it is convenient to use the vigr command to edit the "/etc/group" file. (The operation method is the same as vi)

The user's login history will be output to the /var/run/utmp and /var/log/wtmp files.This file, like the /var/log/lastlog and /var/log/btmp files, is a binary file, so it cannot be displayed by the less, cat, or tail commands.To display it, use the dedicated /usr/bin/last command.

To check which group a particular user belongs to, use the groups command.If you run the command with no arguments, the group to which the user who executed the command belongs will be displayed.If you specify the name of the user whose group you want to display as an argument, the group to which the user belongs will be displayed.