Date command
Display current date, format: 2016-08-08
Show today is the day of the week
Set the current date to 2008-08-0808:08
ls command
Show only hidden files for the specified directory
Displays only directories under the specified directory (without looking at the file)
Displays all files or directories that start with L, end with a lowercase letter, and have at least one digit in the middle of the/var directory
Displays a file or directory that starts with any digit in the/etc directory and ends in a non-numeric number
Displays a file or directory that starts with a non-letter in the/etc/directory followed by a letter and any other character of any length
Displays all files or directories in the/etc directory that begin with a non-numeric end of M
Displays all files or directories ending with. D in the/etc directory
Displays files or directories with the. conf ending with the/etc directory and beginning with m,n,r,p
All files or directories in the display directory that start with 1, end with a lowercase letter, and appear in the middle of an arbitrary character
Displays files or directories that start with any digit in the/etc directory and end with a non-digit
Displays a file or directory that starts with a non-letter, followed by a letter and any other character of any length, in the/etc directory
mkdir command
Using the alias command, each day to the/etc/directory of all files, back up to/testdir/under the new directory, and the new directory format is BACKUPYYYY-MM-DD, the backup process is visible
First create the/testdir/rootdir directory, then copy the/root all the next files into the directory, and ask to retain the original permissions
How to create a/testdir/dir1/x, /testdir/dir1/y,/testdir/dir1/x/a, /testdir/dir1/x/b,/testdir/dir1/y/a,/testdir/dir1/y/b
How to create/TESTDIR/DIR3,/TESTDIR/DIR4,/TESTDIR/DIR5,/testdir/dir5/dir3,/testdir/dir5/dir4
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CP command
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Copy all hidden files in the current directory to the specified folder
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copy/etc directory, all files or directories starting with M, ending with non-digits to the/tmp/magedu.com directory
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copy/usr/share/man directory, All text pieces or directories ending with a man, followed by a number, to the/tmp/man directory
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copy/etc directory, all files or directories ending with. conf and beginning with N,m,r,p to the /tmp/conf.d/directory
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/etc/ The first six lines of the passwd file are converted to uppercase characters after the output
Users and Groups
Create user Gentoo, additional group is bin and root, default shell is/bin/csh, annotation information is "Gentoo distribution"
Create the following user, group, and group memberships
Group with the name Admins
User Natasha, using admins as a subordinate group
User Harry, also use admins as a subordinate group
User Sarah, not interactive login system, and not a member of admins, Natasha, Harry,sarah password are CentOS
TR command
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Convert the contents of the/etc/issue file to uppercase after saving to the/tmp/issue.out file
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Convert the current system logged on user's information to uppercase and save to the/tmp/who.out file
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/root/the list of files to be displayed as a line, separated by a space between the filenames.
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file1 file are: " 1 2 3 4 5 6 7 8 9 10 "Calculates the sum of all numbers
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Delete empty lines of the specified file
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Text Processing tools (grep, regular expressions, cut, head, tail, sort, uniq)
Maximum percent value of partition space usage detected
User name, UID, and shell type with maximum user UID detected
Identify the permissions of/tmp and display them digitally
Counts the number of connections for each remote host IP that is currently connected to this machine and sorts from large to small
Use extended regular expressions to represent 0-9, 10-99, 100-199, 200-249, 250-255, respectively
Remove all whitespace characters from the beginning of lines in the/etc/grub2.conf file that begin with whitespace
Add # At the beginning of each line of/root/install.log
Add # to the beginning of a line in the/etc/fstab file that does not start with #
Statistics for all RPM files in the package directory on the CentOS installation CD-ROM the number of repetitions of the second-to-last field
(Total 40 questions, a-f each question 2 points g each question 4 minutes altogether 98 minutes)
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Linux Basics-Measuring how much you can score