Quoting issue with expect script -

i have script automatically connect vpn, because have connect , disconnect several times day. (certain things screenhero , gotomeeting fail on vpn, , mail servers , other things blocked while on vpn, but can't connect git server unless i'm on vpn, , app i'm working on can't reach back-end services unless i'm on vpn, development limited when disconnected.)

the script lessens hassle, have $ in password (which available in environment through environment variable vpn_password¹), , password value gets interpolated before passed vpn program expect.

#!/bin/bash  {   /usr/bin/expect << end_of_login_session   set timeout 30   spawn /opt/cisco/anyconnect/bin/vpn -s connect blah.blahblah.com   expect "username:*"   send "\r"   expect "password:*"   send "$vpn_password\r"   expect "accept? \[y/n\]:*"   send "y\r"   expect eof end_of_login_session } 

how pass password literally, without letting subject string interpolation?

changing password cop-out. saving \ cop-out (and horrible ux, since have enter every time source .project file project²).

it seems expect must have solution this.

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1. yes know steals laptop try log in, (a) they'd have account first, , (b) they'd fail without pin, entered phone, anyway.

2. no, password not saved disk. enter once per shell session related project.

you have shell variable $vpn_password in unquoted heredoc, shell substitute value. suppose vpn_password='foo$bar' => expect see: send "foo$bar\r" , you'll can't read "bar": no such variable. solution use {braces} instead of double quotes, expect not attempt expand "inner" variable.

send {$vpn_password}; send "\r" 

you need separate send "\r" because putting \r inside braces remove special meaning, , tcl won't let send {$vpn_password}"\r"

here's demo:

$ vpn_password='foo$bar' $ expect <<end send_user "$vpn_password\n" end can't read "bar": no such variable     while executing "send_user "foo$bar\n"" $ expect <<end send_user {$vpn_password}; send_user "\n" end foo$bar 

in tcl, braces act single quotes in shell: inside them literal characters.

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it might cleaner use environment pass values. here implemented shell function

vpnconnect() {     expect <<'end'         set timeout 30         spawn /opt/cisco/anyconnect/bin/vpn -s connect $env(vpn_host)         expect "username:*"         send "\r"         expect "password:*"         send "$env(vpn_password)\r"         expect {accept? [y/n]:*}         send "y\r"         expect eof end }