Linux: How To Use Expect

Here’s a simple expect example:

#!/usr/bin/expect -f
spawn some-script-requiring-input.sh
expect "Enter passphrase:"
send ThisIsMyPassword\n
interact

Another example using variables:

#!/usr/bin/expect -f
set myhost MyCrazyBox
spawn ssh $myhost "ls"
expect $myhost
send "MyPassword"
interact

Another example installing a printer:

#!/usr/bin/expect -f
spawn hp-setup -i -a -x -d hp:/net/hp_color_LaserJet_3500?zc=NPIF944C5
expect "Enter option"
send \n
expect "Do you accept the license terms"
send \n
expect eof

The “eof” is required to end the script cleanly.