tac

tac

The tac command in Linux is used to concatenate and print files in reverse order. It is a useful command for viewing files that are too long to fit on the screen in a single view.

The tac command is used as follows:

tac [options] file

• options: These are optional flags that can be used to control the behavior of the tac command.

• file: This is the file that you want to concatenate and print in reverse order.

For example, the following command will concatenate and print the file file1.txt in reverse order:

tac file1.txt

The tac command will output the contents of the file file1.txt in reverse order, from the last line to the first line.

The tac command is a useful command for viewing files that are too long to fit on the screen in a single view. It can also be used to view files that are sorted in reverse order.

Here are some other examples of how the tac command can be used:

• To concatenate and print multiple files in reverse order:

tac file1.txt file2.txt file3.txt

• To concatenate and print a file in reverse order, starting from a specific line number:

tac -s 10 file1.txt

• To concatenate and print a file in reverse order, skipping every other line:

tac -n 2 file1.txt

The tac command is a versatile command that can be used to concatenate and print files in reverse order. It is a valuable tool for anyone who needs to view files that are too long to fit on the screen in a single view.

help

Usage: tac [OPTION]... [FILE]...
Write each FILE to standard output, last line first.

With no FILE, or when FILE is -, read standard input.

Mandatory arguments to long options are mandatory for short options too.
  -b, --before             attach the separator before instead of after
  -r, --regex              interpret the separator as a regular expression
  -s, --separator=STRING   use STRING as the separator instead of newline
      --help     display this help and exit
      --version  output version information and exit