Learn how to use the sed command to replace specific lines of data in Linux systems

The sed command in Linux is powerful. Today we will introduce in detail how to use the sed command to replace in Linux. Specifically, it is divided into the following situations:

1) How to replace the first searched content;

2) How to replace all matching content in the full text;

3) How to replace the content of a certain line;

4) How to replace the content of multiple lines;

5) How to save the sed replacement result into the original text;

6) How to use multiple sed replacement conditions at the same time;

7) How to use regular expressions.

1, Replace the content found for the first time, The command is as follows:

sed 's/content to be replaced/new content/' file to be processed

As shown below, replace the first lowercase b with an uppercase B.

2, Replace all matching content in the full text, the command is as follows:

sed 's/content to be replaced/new content/g' file to be processed

As shown below, replace all lowercase b's with uppercase B's.

3, Replace the content of a certain line , the command is as follows:

sed 'Line number c new content' File to be processed

As shown below, replace the second line with "new test!"

4, Replace the content of multiple lines , the command is as follows:

sed 'Start line number, end line number c new content' File to be processed

As shown below, replace the second to sixth lines with "new test!"

5. The above replacement commands only display the replacement results on the screen. If you want to save the replacement results directly to the original text, just add the -i parameter . As shown below.

sed -i 's/content to be replaced/new content/g' file to be processed

6. Multiple sed commands can also be connected using the -e parameter to complete multiple operations at one time. As shown in the picture below, first replace the lowercase a with an uppercase A, and then replace the second line with "new test!"

7. Furthermore, regular expressions are allowed in both the replacing and replaced parts of the sed command. For example, the following command replaces all numbers with "ok".

sed 's/[0-9]/Okay/g' testFile2.txt

Notice:

Before entering Linux commands, be sure to switch the input method to English half-width symbols. When copying commands from a Windows computer to Linux Terminal for execution, you may also encounter command execution errors caused by incorrect format. In this case, it is recommended to re-enter the characters manually. If you find it troublesome to enter, you can just delete the spaces and the last character in the command. After that, re-enter the space and the last character.

The above is the detailed content of Learn how to use the sed command to replace specific lines of data in Linux systems. For more information, please follow other related articles on the PHP Chinese website!