Linux shell Command Cat

Cat: View the contents of a file, connect a file, create one or more files, and redirect output to a terminal or file usage: cat [options] [file]

1. $ Cat Hello.txt

displaying content in a hello.txt text file

2. $ cat-n File

-N option to display the contents and line numbers of a file

3. $ cat-b File

-b option, similar to-N, but only identifies line numbers for non-blank lines

4. $ cat-e File

The-e option, which displays the "$" character at the end of each line, is useful when you need to convert multiple lines of content into a single line.

5. $ cat

If you enter only the cat command, it simply receives the standard input and displays it in the standard output, so when you enter a line and press ENTER, the same content is displayed on the next line.

such as: $ cat

Hello world!

Hello world!

$

REDIRECT words:

$ cat >hello

Hello world!

(ctrl+d key combination exits, the input of the content Hello world! will be written to the file Hello)

$ cat Hello

Hello world!

$

There are two redirect operators: > and >>, the former is content overlay, and the latter is the last append of the most files.

6. Connect the contents of multiple files to a new file

$ cat Test test1 > Test2

$ cat Test2

The results will display the contents of test and test1.

Linux shell Command Cat