How to enter "ESC" key in a Python script?

Question

I have logined to a CentOS machine using below Python script:

import paramiko

username = input('Username: ')
password = input('Password: ')

ssh_client = paramiko.SSHClient()
ssh_client.set_missing_host_key_policy(paramiko.AutoAddPolicy())
ssh_client.connect(hostname='192.168.30.129',username=username,password=password,look_for_keys=False)

remote_connection = ssh_client.invoke_shell()
remote_connection.send("mkdir test\n")
remote_connection.send("vi test.txt\n")
remote_connection.send("test\n")
remote_connection.send(":wq\n")
output = remote_connection.recv(65535).decode('ascii')
print (output)

ssh_client.close

What I did with this script:

Login to the CentOS machine using paramiko
Create a folder called 'test'
Create a text file called 'test.txt' using vi and type 'test' in the file.
Type ':wq' in order to save the change I made in 'test.txt' and quit vi.

Step 1 to 3 work perfectly for me, but I couldn't get step 4 done because I don't how to hit "esc" button to enter the Normal Mode of Vi before I'm able to type :wq.

So my question is: How to enter "ESC" key in a Python script?

BTW, on the last line, you probably want to call the close method: `ssh_client.close()` — Jiří Baum, Aug 29 '21 at 08:03
Thanks Baum, I tried remote_connection.send("\xnn"), it returned “UnicodeDecodeError: 'ascii' codec can't decode byte” error. — Parry Wang, Aug 29 '21 at 08:20
Thanks pouria farhadi, using echo works, but I still prefer editing a file using vi. — Parry Wang, Aug 29 '21 at 08:21
Using `vi` from within Paramiko is borderline insane. Is there a particular reason you want to use a tool designed specifically for interactive use? — tripleee, Aug 29 '21 at 09:24
@martineau I have reopened this question; this is unrelated to detecting keypresses in Python. I would have thought there'd be a duplicate about how to represent the _Esc_ character in a string, too, but I could not find one. — tripleee, Aug 29 '21 at 11:26
https://stackoverflow.com/questions/2420671/whats-the-vt100-escape-code-for-the-esc-keyboard-key-itself asks basically the same question, but the answers don't answer that question. — tripleee, Aug 29 '21 at 12:20

score 1 · Accepted Answer · answered Aug 29 '21 at 11:33

Your question lacks an important step; you need to type Esc before you type :wq. This is just another character, though it's not a printable character; it can be represented e.g. with the hex escape code \x1b (similarly, ctrl-A is \x01, ctrl-B is \x02, etc; Esc is also sometimes represented as ctrl-[.)

However, using vi to create a file programmatically is extremely odd; you're much better off using a simple redirection like

echo "test" >test.txt

If you need to write multiple lines, printf is convenient:

printf '%s\n' 'hello' '' 'world' >test.txt

writes the three lines "hello", an empty line, and "world" to the file.

How to enter "ESC" key in a Python script?

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