How can I prevent `expect` from exiting at EOF when reading data from stdin?

Question

When I run echo "passphrase" | expect expect.exp "hostname" echo "passphrase" | expect expect.exp "hostname" , everything works fine, but expect exits immediately.

expect.exp

#!/usr/bin/expect

set passphrase [gets stdin]

set hostname [lindex $argv 0]

spawn ssh admin@$hostname
expect "passphrase"
send "$passphrase\r"
expect "admin@$hostname"
send "clear\r"
interact

Answer 1

interact does not work when stdin is not a tty. You can pass the password as a command line option, just like the hostname.

Answer 2

You might want to use the environment to pass the passphrase:

# shell code
export passphrase="pass phrase"
expect expect.exp hostname

# expect code
...
send "$env(passphrase)\r"