How to use Expect in a Bash script

Question

I am trying to write a script that pulls the latest version of my software from a Git repository and updates the configuration files. When pulling from the repository though, I have to enter a password. I want the script to automate everything, so I need it to automatically fill it in for me. I found this site that explained how to use Expect to look for the password prompt and send the password. I can't get it to work though.

Here's my script:

#!/usr/bin/expect -f
set password [lrange $argv 0 0]
set timeout -1

clear
echo "Updating Source..."
cd sourcedest
git pull -f origin master

match_max 100000
# Look for passwod prompt
expect "*?assword:*"
# Send password aka $password
send -- "$password\r"
# send blank line (\r) to make sure we get back to gui
send -- "\r"
expect eof

git checkout -f master
cp Config/database.php.bak Config/database.php
cp webroot/index.php.bak webroot/index.php
cp webroot/js/config.js.bak webroot/js/config.js

What am I doing wrong?

Here's the site I got it from: http://bash.cyberciti.biz/security/expect-ssh-login-script/

i'm not wanting that part. I'm running this inside my local machine. — LordZardeck, May 01 '12 at 05:33
No git, cd and cp are no valid expect commands. You need to spawn a shell for it. — bdecaf, May 01 '12 at 05:35
No. But you need to use spawn for the git and cp lines. Instead of cd I would add the git-dir to the git command. — bdecaf, May 01 '12 at 05:48
ok, i tried that, but it tells me that's not a git repo, but if I cd to it it works. :p — LordZardeck, May 01 '12 at 05:58
Why do you always have to enter a password when pulling from the remote repository? Is it an ssh or http based remote? Are you sure ssh keys aren't an option? What about storing a username and password in your `.netrc` file? There may be multiple ways of making this whole `expect` script unnecessary. — larsks, May 07 '12 at 00:54

score 22 · Answer 1 · edited Aug 01 '20 at 21:41

This is pretty much taken from the comments, with a few observations of my own. But nobody seems to want to provide a real answer to this, so here goes:

Your problem is you have an Expect script and you're treating it like a Bash script. Expect doesn't know what cd, cp, and git mean. Bash does. You want a Bash script that makes a call to Expect. For example:

#!/usr/bin/env bash

password="$1"
sourcedest="path/to/sourcedest"
cd $sourcedest

echo "Updating Source..."
expect <<- DONE
  set timeout -1

  spawn git pull -f origin master
  match_max 100000

  # Look for password prompt
  expect "*?assword:*"
  # Send password aka $password
  send -- "$password\r"
  # Send blank line (\r) to make sure we get back to the GUI
  send -- "\r"
  expect eof
DONE

git checkout -f master
cp Config/database.php.bak Config/database.php
cp webroot/index.php.bak webroot/index.php
cp webroot/js/config.js.bak webroot/js/config.js

However, as larsks pointed out in the comments, you might be better off using SSH keys. Then you could get rid of the expect call altogether.

How to use Expect in a Bash script

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