To read the last N lines of a file in Linux, you can use various commands and techniques. Here is how you can do it:
- Using tail command: The tail command allows you to display the last N lines of a file. Open the terminal and type the following command, replacing "N" with the desired number of lines: tail -n N filename This will display the last N lines of the specified file.
- Using head and tac commands: You can combine the head and tac commands to achieve the same result. Open the terminal and execute the following command: tac filename | head -n N | tac This will reverse the lines in the file using tac, then use head to display the first N lines, and finally reverse it back using tac to get the original order of lines.
- Using sed command: The sed command is a powerful stream editor that can be used to manipulate text. To read the last N lines of a file using sed, execute the following command: sed -n '{N}p' filename Replace "{N}" with the desired number of lines you want to read.
- Using awk command: The awk command is another text processing tool. To read the last N lines of a file using awk, open the terminal and type: awk 'NR > (total_lines - N)' filename Replace "N" with the number of lines you want to read and replace "total_lines" with the total number of lines in the file.
These methods will allow you to read the last N lines of any file in Linux, providing you with flexibility and control over your file reading operations.
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What is the option to display line numbers while reading the last N lines of a file with tail?
The option to display line numbers while reading the last N lines of a file with tail is -n.
The syntax is as follows:
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tail -n N filename
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This will display the last N lines of the file with line numbers.
How to read the last N lines of a file and append it to another file in Linux?
To read the last N lines of a file and append it to another file in Linux, you can use the tail command to extract the last N lines, and then use the >> operator to append the output to another file. Here is the syntax:
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tail -n N <source_file> >> <destination_file>
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Replace N with the number of lines you want to extract, <source_file> with the file you want to read from, and <destination_file> with the file you want to append the lines to.
For example, to read the last 10 lines of file1.txt and append it to file2.txt, you can use the following command:
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tail -n 10 file1.txt >> file2.txt
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What is the command to read the last N lines of a file in reverse order and save it to a new file?
The tail command can be used to read the last N lines of a file, and the tac command can be used to reverse the order of lines. To save the reversed lines to a new file, you can use the output redirection operator >.
The command to read the last N lines of a file in reverse order and save it to a new file can be written as follows:
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tail -n N file.txt | tac > new_file.txt
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Replace N with the desired number of lines and file.txt with the name of the file you want to read from, and new_file.txt with the name of the file you want to save the reversed lines to.
What is the option to follow and display new lines while reading a file using tail?
The option to follow and display new lines while reading a file using tail is tail -f.
The -f option stands for "follow" and it emulates the tail command to continuously display the content of a file as it grows, by displaying any new lines that are added to the file in real-time. This is particularly useful when monitoring log files or continuously updated files.
How to read the last N lines of a file without displaying the file name in Linux?
To read the last N lines of a file without displaying the file name in Linux, you can use the following command:
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tail -n N filename | sed 's/^.*$/&/'
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Here, replace "N" with the desired number of lines to read from the end of the file, and "filename" with the actual name or path of the file.
Explanation:
- The tail command is used to read the last N lines of a file.
- The -n option specifies the number of lines to display, and "N" should be replaced with the desired number.
- The sed command is used to perform a substituion operation that does not change anything. In this case, the regular expression ^.*$ matches the entire line, and & is a special character that represents the entire matched pattern. So, the sed command essentially keeps the line unchanged.
By default, the tail command will prefix each line with the file name. However, the sed command is used here to replace the file name with itself, effectively removing it from the output.
What is the command to read the last N lines of a file in reverse order?
The tail command in Linux can be used to read the last N lines of a file. To read the last N lines in reverse order, you can combine the tail and tac commands using a pipe.
The command to read the last N lines of a file in reverse order is:
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tail -n N filename | tac
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Replace N with the desired number of lines and filename with the name of the file you want to read. The tail -n N command extracts the last N lines, and the tac command reverses the order of the lines.
