Homework for the second week of 2016-8-13

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

File Management: CP,MV,RM

Cp:

Copy command

Command format:

CP [OPTION] ... [-T] Source (original file) DEST (destination file)
CP [OPTION] ... Source (original file) ... Directory (Directories)
CP [OPTION] ...-t DIRECTORY SOURCE ...

CP SRC DEST
SRC is a file:
If the target does not exist: Creates a new dest and fills the contents of SRC into the dest;
If the directory exists:
If Dest is a file: overwrites the contents of SRC into the dest;
It is recommended to use the-I option for the CP command;
If the dest is a directory: Create a new file with the same name as the original file under Dest and populate the contents of SRC with the new file

CP SRC ... DEST
SRC.: Multiple Files
Dest must exist and be a directory, and other situations will be wrong;

CP SRC DEST
SRC is the directory:
Use option at this time:-R

If Dest does not exist: creates the specified directory and copies all files in the SRC directory to dest;
If dest exists:
If Dest is a file: Error
If Dest is a directory: Copy to this directory

Common options:
-I: Interactive
-r,-r: Recursively copy directories and all internal content;
-A: archive, preserving all attributes of the file, equivalent to-DR--preserv=all
-D: Copy the connection file instead of the source file it points to, do not track the symbolic link--no-dereference--preserv=links
--preserv=[attr_list]
Mode: Permissions
Ownership: Belong to the main group
Timestamp: Time stamp
Links: Link Properties
Xattr: Extended Properties
Context: Security context
All: All
-P:--preserv=mode,ownership,timesamp
-v:--verbose Display Operation process

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    mv:move; Move file
        mv [OPTION] ... [-T] SOURCE DEST
        mv [OPTION] ... SOURCE directory
        MV [OPTION] ...-t DIRECTORY SOURCE ...  

            src is a file:
                if the target does not exist: Creates a new dest, fills the contents of SRC into dest, and deletes the src file
                If the directory exists:
                     If Dest is a file: equivalent to duplicate name
                      If the dest is a directory: Create a new file with the same name as the original file under Dest and populate the SRC content in the new file and delete the SRC directory

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RM Delete a file or directory
RM [OPTION] ... FILE ...

Common options:
-I: Interactive
-F: Force delete
-R: Recursive delete
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2. Bash's work characteristics the command execution status return value and command line expansion are involved in the content and its sample demonstration.
Execution result status of the command
Success/failure: two states

Bash uses a special variable $? Save the execution status result of the most recent command:
0: Success
1-255: Failure

Program execution has two types of results:
The return value of the program:
program execution status results;

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Command line expansion
~: Expand to the user's home directory
~username: Expand the home directory for the development user
{}: Can host a comma-separated list and expand it to multiple paths

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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}

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(2), create/tmp/mylinux directory:

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
[[Email protected]t/]# mkdir-p/ Tmp/mylinux/{bin,boot/grub,dev,etc/{rc.d,sysconfig}/{init.d,network-scripts},lib/modules,lib64,proc,sbin,sys, Tmp,usr/local/{bin,sbin},var,lock,log,run}

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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.
Stat/path/to/somefile: Gets the metadata for the development file:

Time Stamp management tool for files
Touch

View file Status: Stat

Three time stamps:
Access time: Atime, reading the contents of a file
Modify Time: Modified, abbreviated to Mtime, change the file contents (data)
Change time: Changed to CTime, meta data changed

Touch [OPTION] ... [FILE] ...
-A: Only modified access time only Atime
-M: Modify only the modified time Mtime
-T STAMP:
[[Cc]yy] MMDDHHMM[.SS]
-C: If the file does not exist, it is not created

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

Command Aliases (alias)
Implemented by the alias command:
(1) Ailas
Displays all the available command aliases for the current shell process:
(2) Alias Name= ' VALUE '
Defines the alias name, which is equivalent to executing the command value;

Note: Aliases defined on the command line are valid only for the current shell process, and are defined in the configuration file if you want to be permanently valid;
For the current user only: ~/.BASHRC
Valid for all users:/ETC/BASHRC

Note: The new configuration given by the edit configuration will not take effect immediately;

The bash process re-reads the configuration file;
Source/path/to/config_file
. /path/to/config_file

Revoke alias: Unalias
Unalias [-A] name [name ...]

Note: If the alias is the same as the name of the original command, you can use "\command" if you want to execute the original command;

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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.

ls-d/var/l*[[:d igit:]]*[[:lower:]]

ls-d/var/l*[0-9]*[[:lower:]]

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

ls-d/etc/[[:d igit:]]*[^[:d igit:]]

Ls-d/etc/[0-9]*[^0-9]

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

Ls-d/etc/[^[:alpha:]][[:alpha:]]*

Ls-d/etc/[^a-z,a-z][a-z,a-z]*

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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.

Nano/tmp/tfile-2016-08-13-22-09-22

Vi/tmp/tfile-2016-08-13-22-09-23
Vim/tmp/tfile-2016-08-13-22-09-24
touch/tmp/tfile-2016-08-13-22-09-25
echo ' Hello ' >/tmp/tfile-2016-08-13-22-09-26

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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.
Cp-a/etc/p*[^0-9]/tmp/mytest1/
Cp-a/etc/p*[^[:d igit:]]/tmp/mytest1/
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11. Copy all files or directories ending with. D in the/etc directory into the/tmp/mytest2 directory.
Cp-a/etc/*.d/tmp/mytest2

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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.
Cp-a/etc/[l,m,n]*.conf/tmp/mytest3

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Homework for the second week of 2016-8-13