In Linux system, folder is one of the most common file types. In addition to creating a single blank directory, the mkdir command can also recursively create a file directory with nested stack relationship in combination with the - p parameter.

[root@linuxprobe ~]# mkdir linuxprobe 
[root@linuxprobe ~]# cd linuxprobe 
[root@linuxprobe linuxprobe]# mkdir -p a/b/c/d/e 
[root@linuxprobe linuxprobe]# cd a 
[root@linuxprobe a]# cd b 
[root@linuxprobe b]#

3. cp command

The cp command is used to copy files or directories in the format "cp [options] source file destination file". You should be familiar with file copying. In Linux system, copying can be divided into three situations:

• If the destination file is a directory, the source file is copied to that directory
• If the target file is also a normal file, you are asked if you want to overwrite it
• If the target file does not exist, perform the normal copy operation

  Next, use touch to create a file called install Log, and then copy it into a backup file named x.log. Finally, use the ls command to view the files in the directory:

  [root@linuxprobe ~]# touch install.log 
  [root@linuxprobe ~]# cp install.log x.log 
  [root@linuxprobe ~]# ls 
  install.log x.log

4. mv command

6. dd command

dd Command is used to copy or convert files according to the specified size and number of data blocks. The format is“ dd [ parameter ] ".

dd Command is an important and characteristic command. It allows users to copy the contents of files according to the specified size and number of data blocks. Of course, if you like, you can also convert the data during the replication process. There is a file named / dev/zero in the Linux system Every time I explain it in class, it is full of the color of philosophical theory. Because this file does not occupy the system storage space, but can provide endless data, it can be used as the input file of the DD command to generate a file of a specified size. dd The parameters and functions of the command are shown in table 2-13.

For example, we can use the dd command to take a 560MB data block from the / dev/zero device file and save it as 560MB_ File. After understanding this command, you can create files of any size at will:

[root@linuxprobe ~]# dd if=/dev/zero of=560_file count=1 bs=560M 
1+0 records in 
1+0 records out 
587202560 bytes (587 MB) copied, 27.1755 s, 21.6 MB/s

dd The function of the command is not limited to copying files. If you want to make the disc in the optical drive device into iso grid

Image file, in Windows The system needs the help of third-party software, but in Linux The system can directly

use dd Command to suppress the CD image file and program it into an immediately usable iso Mirror image:

[root@linuxprobe ~]# dd if=/dev/cdrom of=RHEL-server-7.0-x86_64-LinuxProbe.Com.iso 
7311360+0 records in 
7311360+0 records out 
3743416320 bytes (3.7 GB) copied, 370.758 s, 10.1 MB/s

Considering that friends will tangle bs Block size and count For the relationship between the number of blocks, the following is an example of eating goods

Explain. Suppose Xiao Ming's appetite (i.e. demand) is a fixed value, and the size of the spoon used to hold rice is bs Block size, and the number of times to serve with a spoon is count Number of blocks. If Xiao Ming wants to be full (meet the demand), he needs to be the size of a spoon( bs block size) and the number of times (count) of serving rice with a spoon Number of blocks). The larger the spoon, the fewer times it is used to serve rice. Visible on the, bs And count They are used to specify the capacity. As long as they can meet the demand, they can be combined and matched at will.