Automating telnet session using bash scripts
While I'd suggest using expect
, too, for non-interactive use the normal shell commands might suffice. telnet
accepts its command on stdin, so you just need to pipe or write the commands into it through heredoc:
telnet 10.1.1.1 <<EOF
remotecommand 1
remotecommand 2
EOF
(Edit: Judging from the comments, the remote command needs some time to process the inputs or the early SIGHUP is not taken gracefully by telnet
. In these cases, you might try a short sleep on the input:)
{ echo "remotecommand 1"; echo "remotecommand 2"; sleep 1; } | telnet 10.1.1.1
In any case, if it's getting interactive or anything, use expect
.
Write an expect
script.
Here is an example:
#!/usr/bin/expect
#If it all goes pear shaped the script will timeout after 20 seconds.
set timeout 20
#First argument is assigned to the variable name
set name [lindex $argv 0]
#Second argument is assigned to the variable user
set user [lindex $argv 1]
#Third argument is assigned to the variable password
set password [lindex $argv 2]
#This spawns the telnet program and connects it to the variable name
spawn telnet $name
#The script expects login
expect "login:"
#The script sends the user variable
send "$user "
#The script expects Password
expect "Password:"
#The script sends the password variable
send "$password "
#This hands control of the keyboard over to you (Nice expect feature!)
interact
To run:
./myscript.expect name user password