Linux Base command (TEN) Cat command

The purpose of the cat command is to connect files or standard input and print. This command is often used to display the contents of a file, or to connect several files to a display, or to read content from standard input and display it, often in conjunction with a redirection symbol.

1. Command format:

Cat [Options] [file] ...

2. Command function:

Cat has three main functions:

1. Display the entire file at once: Cat filename

2. Create a file from the keyboard: cat > FileName can only create new files and cannot edit existing files.

3. Merging several files into one file: Cat file1 file2 > file

3. Command parameters:

-A,--show-all equivalent to-vet

-B,--number-nonblank for non-null output line numbering

-e equivalent to-ve

-E,--show-ends displays $ at end of each line

-N,--number all row numbers for the output, numbering the number of rows for all outputs starting with 1

-S,--squeeze-blank has two consecutive rows of blank lines, the substitution of a line of blank lines

-T and-VT equivalence

-T,--show-tabs displays the ^i character as a

-U (ignored)

-V,--show-nonprinting use ^ and M references, except LFD and TAB

4. Use instance:

Example one: The Log2012.log file content with the line number after the input log2013.log this file

Command:

Cat-n Log2012.log Log2013.log

Output:

[Root@localhost test]# Cat Log2012.log

2012-01

2012-02

======[root@localhost test]# Cat Log2013.log

2013-01

2013-02

2013-03

======[root@localhost test]# cat-n Log2012.log log2013.log

1 2012-01

2 2012-02

3

4

5 = = =

6 2013-01

7 2013-02

8

9

10 2013-03

One ======[root@localhost test]#

Description

Example two: Append the contents of Log2012.log and Log2013.log to Log.log after adding line numbers (blank lines).

Command:

Cat-b Log2012.log Log2013.log Log.log

Output:

[Root@localhost test]# cat-b log2012.log log2013.log log.log

1 2012-01

2 2012-02

3 = = =

4 2013-01

5 2013-02

6 2013-03

7 = = = [Root@localhost test]#