Second week homework

1. What are the file management commands on Linux, their commonly used methods and their related examples?

CP Copy Command

-I: Interactive

-r,-r: Recursively copy all contents of a directory and content

-A: Archive, equivalent to-DR--preserve=all

-P: Preserve properties of copied files

-V: Show more information

-F: Forced replication

Example: cp/etc/inittab/tmp

MV Move Command

-I: Interactive

-F: Force move

Example: mv/etc/inittab/tmp

RM Delete command

-I: Interactive

-F: Strong delete

-R: Recursive delete

Example: rm/etc/inittab/tmp

LS View file

-L: Viewing files in long form

-A: View all files

-T: Arranged by time

-R: Flashback view File

Example: Ls-l/etc/inittab

Cat viewing the contents of a file

Example: Cat/etc/inittab View the contents of a file

2. Bash's work characteristics the command execution status return value and command line expansion are involved in the content and its sample demonstration.

echo $? View command execution status return value

0 indicates success

1 indicates failure

2-255 indicates an error

Command line expansion: ~, {}

~: Indicates the current user's home directory

CD ~: Indicates the home directory of the currently logged in user

Mkdir/tmp/{a,b}_{c,d} {} means expand

3. Use the command line expansion function to complete the following exercises:

(1), create/tmp directory: A_c, A_d, B_c, B_d

MKDIR/TMP/{A,B}_{C,D}

(2), create the/tmp/mylinux directory:

Mkdir-p/tmp/mylinux/{bin,boot/grub,dev,etc/{rc.d/init.d,sysconfig/network-scripts},lib/modules,lib64,proc,sbin , Sys,tmp,usr/local/{bin,sbin},var,lock,log,run}

4, what is the metadata information of the file, what does it mean, how to view it? How to modify timestamp information for a file.

Ls-l file name: You can view the metadata of files

Meta data information is:

File type: Permissions: Number of hard Links: Owner: Genus Group: Access time: File name

The timestamp of the file can be divided into Access time, modification time, change time

Touch file name indicates the timestamp of the modified file

5, how to define the alias of a command, how to reference the execution result of another command in the command?

Alias cdnet= "Cd/etc/sysconfig/network-scripts"

Ls-l/var | Wc-l using pipelines To reference the execution result of another command in a command

6. Display all files or directories in the/var directory that start with L, end with a lowercase letter, and have at least one digit (can have other characters) appear in the middle.

Cd/var

Ls-ld L*[0-9]*[[:lower:]]

7. Displays files or directories that start with any number in the/etc directory and end with a non-numeric number.

Cd/etc

Ls-ld [0-9]*[^0-9]

8, Show/etc directory, start with a non-letter, followed by a letter and any other arbitrary length of any character file or directory.

Cd/etc

Ls-ld [^[:alpha:]][[:alpha:]]*

9. In the/tmp directory, create a file that starts with Tfile, followed by the current date and time, with a filename such as: tfile-2016-08-06-09-32-22.

Cd/tmp

Touch tfile-' Date +%y-%m-%d-%h-%m-%s '

10. Copy all the files or directories in the/etc directory to the/tmp/mytest1 directory that begin with P and do not end with a number.

Mkdir/tmp/mytest1

Cd/etc

Cp-r P*[^0-9]/tmp/mytest1

11. Copy all files or directories ending with. D in the/etc directory into the/tmp/mytest2 directory.

Mkdir/tmp/mytest2

Cd/etc

Cp-r *.d/tmp/mytest2

12. Copy all files in the/etc/directory that begin with L or M or N and end with. conf to the/TMP/MYTEST3 directory.

Mkdir/tmp/mytest3

Cd/etc

Cp-r [L,m,n]*.conf/tmp/mytest3

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Second week homework