nixpkgs/pkgs/build-support/fetchsvnssh/sshsubversion.exp

#!/nix/var/nix/profiles/default/bin/expect -f

# Set variables
set username [lindex $argv 0]
set password [lindex $argv 1]
set rev [lindex $argv 2]
set url [lindex $argv 3]
set out [lindex $argv 4]
set timeout -1

spawn svn export -r$rev svn+ssh://$username@$url $out
match_max 100000

expect "*continue connecting*" { send -- "yes\r"; expect "*?assword:*"; send -- "$password\r" } \
       "*?assword:*" { send -- "$password\r" }

expect "*?assword:*"
send -- "$password\r"

# Send blank line
send -- "\r"
expect eof