tail last 100 lines with code examples

Tailing the Last 100 Lines of a File

In many situations, you may need to view only the last few lines of a large log file or a text file. This can be easily achieved with the tail command. The tail command, by default, displays the last 10 lines of a file, but you can specify the number of lines to be displayed. In this article, we will be discussing how to tail the last 100 lines of a file with code examples.

What is the 'tail' Command?

The tail command is a utility in Unix-like operating systems that is used to display the last part of a file, usually the last few lines. It is used to monitor changes to files and can be useful in debugging applications, especially when combined with other commands like grep and sed. The tail command reads the file from the end, and as new lines are added to the file, it displays them in real-time.

Syntax

The basic syntax of the tail command is as follows:

tail [options] [file_name]

Options

Here are some of the options that can be used with the tail command:

• -f: This option allows tail to monitor the file for changes and display any new lines as they are added.
• -n: This option is used to specify the number of lines to be displayed. For example, tail -n 100 will display the last 100 lines of the file.
• -q: This option is used to suppress the header and footer information that is usually displayed with the tail command.

Examples

Let's look at some examples of how to use the tail command to tail the last 100 lines of a file.

Example 1: Tailing the Last 100 Lines of a File

tail -n 100 file.txt

In this example, the tail command is used to display the last 100 lines of the file file.txt. The -n option is used to specify the number of lines to be displayed, which is 100 in this case.

Example 2: Tailing the Last 100 Lines of a File in Real-Time

tail -f -n 100 file.txt

In this example, the tail command is used to monitor the file file.txt for changes and display any new lines as they are added. The -f option is used to enable this feature, and the -n option is used to specify the number of lines to be displayed, which is 100 in this case.

Example 3: Tailing the Last 100 Lines of Multiple Files

tail -n 100 file1.txt file2.txt file3.txt

In this example, the tail command is used to display the last 100 lines of multiple files, file1.txt, file2.txt, and file3.txt. The -n option is used to specify the number of lines to be displayed, which is 100 in this case.

Conclusion

In this article, we discussed how to use the tail command to tail the last 100 lines of a file. We covered the basic syntax of the tail command and explained some of the options that can be used with it. We also provided examples of how to use the tail command in different scenarios, including tailing the last 100 lines of a file in
Adjacent Topics to "Tailing the Last 100 Lines of a File"

1. Using the head Command

The head command is similar to the tail command but works in the opposite direction. It displays the first few lines of a file, and the default number of lines displayed is 10. The basic syntax of the head command is as follows:

head [options] [file_name]

Some of the options that can be used with the head command are:

• -n: This option is used to specify the number of lines to be displayed. For example, head -n 100 will display the first 100 lines of the file.
• -q: This option is used to suppress the header and footer information that is usually displayed with the head command.

2. Using the grep Command

The grep command is used to search for patterns in a file. It is an extremely powerful tool that can be used to filter log files and search for specific information. The basic syntax of the grep command is as follows:

grep [options] pattern [file_name]

Some of the options that can be used with the grep command are:

• -v: This option is used to invert the match, displaying all lines that do not match the pattern.
• -i: This option is used to perform a case-insensitive search.
• -l: This option is used to display only the names of the files that contain the match.

3. Using the sed Command

The sed command is used to perform text transformations on a file. It can be used to remove lines that match a pattern, replace text, and perform other operations on a file. The basic syntax of the sed command is as follows:

sed [options] [script] [file_name]

Some of the options that can be used with the sed command are:

• -n: This option is used to suppress the default output of sed.
• -i: This option is used to edit the file in place, meaning that the changes made by sed are saved to the file.

By combining these commands, you can perform complex operations on log files, text files, and other types of files. For example, you can use the grep command to filter a log file for specific information, and then use the sed command to remove lines that match a pattern, or replace text. The tail command can then be used to view the last few lines of the filtered and transformed file.

In conclusion, the tail, head, grep, and sed commands are essential tools for anyone who works with text files and log files on a regular basis. They offer a quick and easy way to view, filter, and transform large amounts of data, and can be extremely useful in debugging applications and performing other tasks.

Popular questions

1. What is the purpose of the tail command in Unix-like operating systems?

The purpose of the tail command in Unix-like operating systems is to display the last few lines of a text file. By default, the tail command displays the last 10 lines of a file, but this can be adjusted using the -n option to display a specific number of lines.

2. How do you use the tail command to display the last 100 lines of a file?

You can use the tail command to display the last 100 lines of a file by using the -n option followed by the number 100, like this:

tail -n 100 file_name.txt

3. Can the tail command be used to display the last 100 lines of multiple files at the same time?

Yes, the tail command can be used to display the last 100 lines of multiple files at the same time. To do this, you simply need to specify the names of all of the files that you want to view, separated by spaces:

tail -n 100 file_1.txt file_2.txt file_3.txt

4. What are some of the other options that can be used with the tail command?

There are several other options that can be used with the tail command, including:

• -f: This option is used to continuously display the last few lines of a file as it grows, allowing you to see new data as it is added to the file.
• -q: This option is used to suppress the header and footer information that is usually displayed with the tail command.
• -v: This option is used to display the header and footer information that is usually suppressed by the -q option.

5. Can the tail command be used to display the last 100 lines of a file in real-time?

Yes, the tail command can be used to display the last 100 lines of a file in real-time by using the -f option. This option allows you to continuously display the last few lines of a file as it grows, so that you can see new data as it is added to the file:

tail -n 100 -f file_name.txt

Tag

File-Management