mkdir -p ~/.ssh/

To overwrite authorized_keys

cat ~/.ssh/authorized_keys

To append to the end of authorized_keys

cat >~/.ssh/authorized_keys

cat 的使用

The “cat” command in Linux is a command line utility that is used to concatenate and display the contents of one or more files on the terminal. The name “cat” stands for “concatenate”.

The basic syntax of the “cat” command is:

cat [options] [file(s)]

Here, the options are used to specify various settings for the command, and the file(s) argument specifies the name(s) of the file(s) whose contents are to be displayed.

Some common options that can be used with the “cat” command include:

-n: displays line numbers before each line of the file.
-b: displays line numbers before each non-blank line of the file.
-s: squeezes multiple adjacent blank lines into a single blank line.
For example, to display the contents of a file named “example.txt” on the terminal, you can use the following command:

cat example.txt

This will display the contents of the “example.txt” file on the terminal.

In Linux, the “cat >” and “cat >>” commands are used to redirect the output of a command or a file into a new file.

The “cat >” command is used to create a new file or overwrite the contents of an existing file with the output of a command or the contents of a file. The basic syntax is:

cat [file(s)] > [new_file]

For example, to create a new file named “new_file.txt” and copy the contents of an existing file “old_file.txt” into it, you can use the following command:

cat old_file.txt > new_file.txt

If “new_file.txt” already exists, the above command will overwrite its contents with the contents of “old_file.txt”.
The “cat >>” command is used to append the output of a command or the contents of a file to an existing file without overwriting its existing contents. The basic syntax is:

cat [file(s)] >> [existing_file]

For example, to append the contents of a file named “data.txt” to an existing file named “existing_data.txt”, you can use the following command:

cat data.txt >> existing_data.txt

This will add the contents of “data.txt” to the end of “existing_data.txt” without overwriting its existing contents.