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LinuxTips(RedHat)_en

Set up an administrator for the group.

You can set up an administrator for an existing group separately from root (privileged user).The administrator set here can add and remove members, set and remove group passwords, etc. for the group.To set up an administrator, add the option "-A" to the gpasswd command and specify the user name and the group name to be managed as arguments.Multiple users can be specified by separating them with a comma ",".
LinuxTips(RedHat)_en

Adding and removing members to a group

●Add members to a groupTo add a member to an existing group, run the gpasswd command with the option "-a".The argument is the name of the user or group to be added and executed.This process can be executed by root or a user registered as a group administrator.
Directory and file operations

Show all files in a directory

To view the files in a directory, use the "ls" command. However, files beginning with a ". (dot) is a hidden file and cannot be displayed by the "ls" command.." (dot), you can use the "ls" command with the option "-a".
Directory and file operations

Checking symbolic links

A symbolic link looks like a normal file, but the actual file is in a different directory. To check whether a file is a symbolic link or not, run the ls command with the "-l" option.
Directory and file operations

Change the default permissions for files and directories

When you create a new file or directory, it will have default permissions. To change the default permissions, use the umask command.Permissions in octal notationflag notation     rwxcorresponding octal number      421
Directory and file operations

Changing the ownership of files and directories

To change the ownership of a file or directory, use the chown command.If you want to change the ownership of all files in a directory, run it with the -R option.
Directory and file operations

Create a multi-level directory in one go

To create a directory, specify the directory name as the argument of the "mkdir" command and execute it, but if you specify a directory that does not exist when specifying a directory over a multi-level hierarchy, an error will occur.In such a case, you can force a non-existent directory to be created and create a multi-level directory at once by executing with the option "-p".
Directory and file operations

Delete the directory (and everything in it)

Delete the directory (and everything in it)To remove a direc...
Directory and file operations

Check the number of characters and lines in a file

The wc command is used to check the number of characters and lines in a file. To check the number of characters, use "-c" as an option, and to check the number of lines, use "-l".To execute the wc command, specify the name of the file you want to investigate as an argument.
Directory and file operations

Display the contents of a file with line numbers

To display the contents of a file, use the cat command, but if you run it without options, it will simply display the contents. To display the contents of a file with line numbers, run the cat command with the option '-n'.If you don't want to add line numbers to blank lines in the file, add the option "-b".
Directory and file operations

Create an empty file (zero bytes)

To create an empty file, use the touch command, which changes the type stamp of a file, but creates a zero-byte file if the argument is a non-existent file.
Directory and file operations

Search files for strings

Use the find command to search for files that exist in your Linux system.find <Directory name> <Option> <File name>Set each argument to a value and perform the search.The directory name is the name of the directory from which the file search will be performed.The find command searches the specified directory and all subdirectories below it.(An error will occur if you search for a directory that cannot be referenced with permissions.)option allows you to specify what files to search. For example, you can search only for directories, or only for files that belong to a certain owner.
Directory and file operations

Compressed in GZIP format, GZIP format decompression

GZIP is the most commonly used compression method for files on Linux.It is usually used to reduce the size of a file by compressing it into a single (archived) file using the tar command.
Directory and file operations

Name your files with dates etc.

Name your files with dates etc.The command to append a date to a file name is the 'date' command.●How to use the date command$ date2020 Septembe 23 Wednesday 00:11:21 JST----------------------------------------------------------The date is now displayed. Now run it as follows----------------------------------------------------------$ date +%Y%m%d20200923-------------------------
Directory and file operations

Search for and delete specific files

The find command can be used to search for and remove files that have certain things in common.The arguments are the directory to be searched, the criteria for the files to be searched, the -ok option or the -exec option, and the delete command rm.