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This article mainly explains "the tutorial of using xargs command in Linux system". Interested friends may wish to have a look at it. The method introduced in this paper is simple, fast and practical. Let's let the editor take you to learn the tutorial on using xargs commands in Linux system.

The xargs command has two main points. First, you must list the target file. Second, you must specify the commands or scripts to be executed for each file.

This tutorial covers three application scenarios, where the xargs command is used to work with files distributed in different directories:

Calculate the number of lines in all files

Prints the first line of the specified file

Execute a custom script for each file

Take a look at the following directory called xargstest (the directory tree structure is shown with the tree command and the-I and-f options, which avoids indentation and each file has a full path):

$tree-if xargstest/

The contents of these six documents are as follows:

This xargstest directory, along with the subdirectories and files it contains, will be used in the following example.

Scenario 1: calculate the number of lines for all files

As mentioned earlier, the first point of using the xargs command is a list of files used to run the command or script. We can use the find command to identify and list the target file. Option-name 'file??' Specifies that files in the xargstest directory whose names begin with "file" and follow two arbitrary characters are matched. This search is recursive by default, meaning that the find command searches for matching files in xargstest and its subdirectories.

The code is as follows:

$find xargstest/-name 'file??'

The code is as follows:

Xargstest/dir3/file3B

Xargstest/dir3/file3A

Xargstest/dir1/file1A

Xargstest/dir1/file1B

Xargstest/dir2/file2B

Xargstest/dir2/file2A

We can pipe the results to the sort command to arrange the file names in order:

The code is as follows:

$find xargstest/-name 'file??' | sort

The code is as follows:

Xargstest/dir1/file1A

Xargstest/dir1/file1B

Xargstest/dir2/file2A

Xargstest/dir2/file2B

Xargstest/dir3/file3A

Xargstest/dir3/file3B

Then we need the second element, which is the command that needs to be executed. We use the wc command with the-l option to calculate the number of newline characters contained in each file (which will be printed before each line of the output):

The code is as follows:

$find xargstest/-name 'file??' | sort | xargs wc-l

The code is as follows:

1 xargstest/dir1/file1A

2 xargstest/dir1/file1B

3 xargstest/dir2/file2A

4 xargstest/dir2/file2B

5 xargstest/dir3/file3A

6 xargstest/dir3/file3B

21 total

As you can see, instead of manually executing the wc-l command on each file, the xargs command allows you to do everything in one step. Tasks that seemed impossible before, such as working with hundreds of files separately, can now be done fairly easily.

Scenario 2: print the first line of the specified file

Now that you have some basis for using xargs commands, you are free to choose which commands to execute. Sometimes, you may want to perform operations on only some files and ignore others. In this case, you can use the-name option of the find command as well as? Wildcards (which match any single character) select a specific file and pipe it to the xargs command. For example, if you want to print a file that ends with a "B" character and ignores the first line of a file that ends with "A", you can use the following combination of find, xargs, and head commands (head-N1 prints the first line of a file):

The code is as follows:

$find xargstest/-name 'file?B' | sort | xargs head-N1

The code is as follows:

= = > xargstest/dir1/file1B xargstest/dir2/file2B xargstest/dir3/file3B

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