if 0 {you may need to download psftp: https://www.puttygen.com/psftp}

set u demo
set p password
set id [spawn psftp.exe test.rebex.net -P 22]

expect -i $id "*login *:" { exp_send -i $id "${u}\r" } \
              "timeout"   { puts "login timout" }       \
              "default"   { puts "login no match" }

expect -i $id "*assword:"  { exp_send -i $id "${p}\r" } \
              "timeout"    { puts "password timeout" } \
              "default"    { puts "password no match" }

expect -i $id "*psftp>*"   { puts "OK"}

set u demo
set p password
set id [spawn psftp.exe test.rebex.net -P 22]

expect -i $id "login *: "  { exp_send -i $id "${u}\r" } \
        "timeout"   { puts "login timout" }       \
        "default"   { puts "login no match" }

expect -i $id "*assword: " { exp_send -i $id "${p}\r\n" } \
        "timeout"    { puts "password timeout" } \
        "default"    { puts "password no match" }

;# added this line but it made no difference
expect -i $id "*\n"       { exp_send -i $id "\r\n"           }

expect -i $id "*psftp> "   { puts "GOT IN" } \
        "timeout"    { puts "session timeout" } \
        "default"    { puts "session no match" }

expect: does "" (spawn_id exp2) match glob pattern "login *: "? no
login as:
expect: does "login as: " (spawn_id exp2) match glob pattern "login *: "? yes
expect: set expect_out(0,string) "login as: "
expect: set expect_out(spawn_id) "exp2"
expect: set expect_out(buffer) "login as: "
send: sending "demo\r" to { exp2 }

expect: does "" (spawn_id exp2) match glob pattern "*assword: "? no
| Password:
expect: does "| Password: " (spawn_id exp2) match glob pattern "*assword: "? yes
expect: set expect_out(0,string) "| Password: "
expect: set expect_out(spawn_id) "exp2"
expect: set expect_out(buffer) "| Password: "
send: sending "password\r\n" to { exp2 }

expect: does "" (spawn_id exp2) match glob pattern "*\n"? no

expect: does "\n" (spawn_id exp2) match glob pattern "*\n"? yes
expect: set expect_out(0,string) "\n"
expect: set expect_out(spawn_id) "exp2"
expect: set expect_out(buffer) "\n"
send: sending "\r\n" to { exp2 }

expect: does "" (spawn_id exp2) match glob pattern "*psftp> "? no
expect: timed out

fconfigure $id -blocking 0 -buffering none

$ sudo apt-get install expect

It installs expect and autoexpect

$ which expect
/usr/bin/expect
$ which autoexpect
/usr/bin/autoexpect

Test expect

$ expect
expect1.1>
expect1.1> exit

Test autoexpect

$ autoexpect
autoexpect started, file is script.exp
$
$ exit
exit
autoexpect done, file is script.exp
$

$ sudo apt install putty putty-tools

Install putty and check. 

$ which putty
/usr/bin/putty

$ putty --version
PuTTY: Release 0.81
Build platform: 64-bit Unix (GTK + X11)
Compiler: gcc 13.2.0
Compiled against GTK version 3.24.41
Source commit: a8601a72a918dfc2a8e8536a77139d7f37700044

$ which psftp
/usr/bin/psftp

$ psftp test.rebex.net -P 22
The host key is not cached for this server:
  test.rebex.net (port 22)
You have no guarantee that the server is the computer you
think it is.
The server's ssh-ed25519 key fingerprint is:
  ssh-ed25519 255 SHA256:d7Te2DHmvBNSWJNBWik2KbDTjmWtYHe2bvXTMM9lVg4
If you trust this host, enter "y" to add the key to PSFTP's
cache and carry on connecting.
If you want to carry on connecting just once, without adding
the key to the cache, enter "n".
If you do not trust this host, press Return to abandon the
connection.
Store key in cache? (y/n, Return cancels connection, i for more info) y
login as: 

*** OR using sftp''' using login: demo  Password : password ***

$ sftp -P 22 [email protected] 
The authenticity of host 'test.rebex.net (194.108.117.16)' can't be established.
ED25519 key fingerprint is SHA256:d7Te2DHmvBNSWJNBWik2KbDTjmWtYHe2bvXTMM9lVg4.
This key is not known by any other names.
Are you sure you want to continue connecting (yes/no/[fingerprint])? y
Please type 'yes', 'no' or the fingerprint: yes
Warning: Permanently added 'test.rebex.net' (ED25519) to the list of known hosts.
Welcome to test.rebex.net! See https://test.rebex.net/ for more information.
([email protected]) Password: 
stfp>




So to use autoexpect to generate the expect script, see below and type your commands interactively.

$ autoexpect psftp test.rebex.net -P 22

autoexpect started, file is script.exp
login as: demo
Pre-authentication banner message from server:
| Welcome to test.rebex.net! See https://test.rebex.net/ for more information.
End of banner message from server
Keyboard-interactive authentication prompts from server:
| Password: 
End of keyboard-interactive prompts from server
Remote working directory is /
psftp> ls
Listing directory /
drwx------ 2 demo users          0 Mar 31  2023 .
drwx------ 2 demo users          0 Mar 31  2023 ..
drwx------ 2 demo users          0 Mar 31  2023 pub
-rw------- 1 demo users        379 Sep 19  2023 readme.txt
psftp> exit
autoexpect done, file is script.exp

$ more script.exp
#!/usr/bin/expect -f
#
# This Expect script was generated by autoexpect on Thu Jul  3 14:36:06 2025
# Expect and autoexpect were both written by Don Libes, NIST.
#
# Note that autoexpect does not guarantee a working script.  It
# necessarily has to guess about certain things.  Two reasons a script
# might fail are:
#
# 1) timing - A surprising number of programs (rn, ksh, zsh, telnet,
# etc.) and devices discard or ignore keystrokes that arrive "too
# quickly" after prompts.  If you find your new script hanging up at
# one spot, try adding a short sleep just before the previous send.
# Setting "force_conservative" to 1 (see below) makes Expect do this
# automatically - pausing briefly before sending each character.  This
# pacifies every program I know of.  The -c flag makes the script do
# this in the first place.  The -C flag allows you to define a
# character to toggle this mode off and on.

set force_conservative 0  ;# set to 1 to force conservative mode even if
                          ;# script wasn't run conservatively originally
if {$force_conservative} {
        set send_slow {1 .1}
        proc send {ignore arg} {
                sleep .1
                exp_send -s -- $arg
        }
}

#
# 2) differing output - Some programs produce different output each time
# they run.  The "date" command is an obvious example.  Another is
# ftp, if it produces throughput statistics at the end of a file
# transfer.  If this causes a problem, delete these patterns or replace
# them with wildcards.  An alternative is to use the -p flag (for
# "prompt") which makes Expect only look for the last line of output
# (i.e., the prompt).  The -P flag allows you to define a character to
# toggle this mode off and on.
#
# Read the man page for more info.
#
# -Don


set timeout -1
spawn psftp test.rebex.net -P 22
match_max 100000
expect -exact "login as: "
send -- "demo\r"
expect -exact "demo\r
Pre-authentication banner message from server:\r
| Welcome to test.rebex.net! See https://test.rebex.net/ for more information.\r
End of banner message from server\r
Keyboard-interactive authentication prompts from server:\r
| Password: "
send -- "password\r"
expect -exact "\r
End of keyboard-interactive prompts from server\r
Remote working directory is /\r
psftp> "
send -- "ls\r"
expect -exact "ls\r
Listing directory /\r
drwx------ 2 demo users          0 Mar 31  2023 .\r
drwx------ 2 demo users          0 Mar 31  2023 ..\r
drwx------ 2 demo users          0 Mar 31  2023 pub\r
-rw------- 1 demo users        379 Sep 19  2023 readme.txt\r
psftp> "
send -- "exit\r"
expect eof