Make a shell script execute commands in telnet or programs

I would like to make a shell script that executes commands on a device that I telnet to or in programs such as FTP or OpenSSL. I have already found a method in FTP, which would look something like this:

#!/bin/sh
HOST='0.0.0.0'
USER='User'
PASSWD='Pass'
FILE='~/Desktop/file.txt'
RFILE='file.txt'

ftp -n $HOST <<END_SCRIPT
quote USER $USER
quote PASS $PASSWD
binary
passive
put $FILE $RFILE
quit
END_SCRIPT
exit 0

How can I do something similar with devices I telnet to or in different programs?

Answers:

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Method 1

some time ago I needed something similar. You can try with something like this:

#!/bin/sh

HOST='0.0.0.0'
USER='User'
PASSWD='Pass'
CMD=''

(
echo open "$HOST"
sleep 2
echo "$USER"
sleep 2
echo "$PASSWD"
sleep 2
echo "$CMD"
sleep 2
echo "exit"
) | telnet

PS1: I user “sleep 2” because I am accessing through satellite. If it’s LAN, maybe you don’t need “sleep” at all.

PS2: just enter what you need in the CMD variable

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