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This article mainly introduces the relevant knowledge of "what is the use of Linux's tac command". The editor shows you the operation process through an actual case, the operation method is simple and fast, and it is practical. I hope this article "what is the use of Linux's tac command" can help you solve the problem.

Linux commonly used command tac happens to reverse cat, so its function is the opposite of cat. Cat is displayed continuously on the screen from the first line to the last line, while tac is displayed on the screen in reverse from the last line to the first line.

Tac connects multiple files and prints them back to standard output in behavioral units.

Summary tac [OPTION]... [FILE]... The main purpose is to display the contents of the file in reverse by the behavior unit, and if there is no file or the file is -, then read the standard input.

When working with multiple files, each file is displayed in reverse in turn, rather than connecting all the files together and then displaying them in reverse.

Parameter FILE (optional): the file to be processed can be one or more.

The option long option is equivalent to the short option-b,-- before concatenates the delimiter before rather than after. -r,-- regex treats the delimiter as the underlying regular expression (BRE). -s,-- separator=STRING uses STRING as the delimiter instead of the default newline character. -- help displays help information and exits. -- version displays version information and exits. The return status of the return value is successful unless an illegal option or parameter is given.

Example # selected from the official info document example: # character after character reversal of a file: tac-r-s'x\ | [^ x] 'test.log # about-b option: seq 1 3 | tac # output 3 2 1 # use-b option: seq 1 3 | tac-b # output Note that there is no newline character after 21: 321 # the previous example is equivalent to converting'1\ N2\ n3\ n` to'3\ N2\ n1\ n' # the previous example is equivalent to converting'1\ N2\ n3\ n' to'\ n\ n3\ n21'. Note that this command is a command in the GNU coreutils package. For help, please see man-s 1 tac or info coreutils' tac invocation'.

For more information about the underlying regular expression (BRE), see the REGULAR EXPRESSIONS paragraph of man-s 1 grep.

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