Introduction

The Linux command tac is a utility that reads a file from the end to the beginning, and prints it to the standard output. It is the reverse of the cat command, which reads a file from the beginning to the end. tac is useful for viewing the last few lines of a file, or for reversing the order of lines in a file. It can also be used to concatenate multiple files in reverse order.

Examples

The tac command is a Linux command used to concatenate and print files in reverse. It is the reverse of the cat command, which prints files in the same order as they appear in the file.

Syntax: tac [OPTION]… [FILE]…

Options:
-b, –before: Insert a line of separator before each file
-r, –regex: Interpret the separator as a regular expression
-s, –separator=STRING: Use STRING as the separator instead of newline

Example:

tac file1.txt

This command will print the contents of file1.txt in reverse order.

Using the tac Command in Linux

The tac command in Linux is a utility that reads from standard input and writes to standard output in reverse order. It is the reverse of the cat command, which reads from standard input and writes to standard output in the same order. The tac command is useful for viewing files in reverse order, such as log files.

The syntax for the tac command is as follows:

tac [options] [file]

The options for the tac command are as follows:

• -b: Outputs a backspace character before each line.
• -r: Reverses the order of the lines.
• -s: Joins lines that end with a backslash.

To view a file in reverse order, use the following command:

tac filename

To view a file in reverse order, with each line preceded by a backspace character, use the following command:

tac -b filename

The tac command is a useful tool for viewing files in reverse order. It can be used to view log files, or any other file that needs to be viewed in reverse order.