diff --git a/how-to-create-encrypted-paper-backup/README.md b/how-to-create-encrypted-paper-backup/README.md
index ea85e38..33d54c1 100644
--- a/how-to-create-encrypted-paper-backup/README.md
+++ b/how-to-create-encrypted-paper-backup/README.md
@@ -85,7 +85,7 @@ Select “Localisation Options”, then “Keyboard”, then “Generic 105-key
 ```console
 $ sudo apt update
 
-$ sudo apt install -y fim imagemagick
+$ sudo apt install -y expect fim imagemagick
 
 $ pip3 install mnemonic pillow qrcode --user
 
diff --git a/how-to-create-encrypted-paper-backup/test.sh b/how-to-create-encrypted-paper-backup/test.sh
new file mode 100755
index 0000000..b61f1de
--- /dev/null
+++ b/how-to-create-encrypted-paper-backup/test.sh
@@ -0,0 +1,20 @@
+#!/bin/bash
+
+set -e
+set -o pipefail
+
+bold=$(tput bold)
+normal=$(tput sgr0)
+
+printf "$bold%s$normal\n" "Please type root password and press enter"
+read -rs password
+
+export password=$password
+
+printf "%s\n" "Running unit tests…"
+
+expect ./tests/bip39.exp
+expect ./tests/electrum.exp
+expect ./tests/default.exp
+expect ./tests/shamir.exp
+expect ./tests/shamir2of3.exp
diff --git a/how-to-create-encrypted-paper-backup/tests/bip39.exp b/how-to-create-encrypted-paper-backup/tests/bip39.exp
new file mode 100644
index 0000000..df7c5ef
--- /dev/null
+++ b/how-to-create-encrypted-paper-backup/tests/bip39.exp
@@ -0,0 +1,190 @@
+#!/usr/bin/expect
+
+# exp_internal 1
+# log_file -noappend ~/expect.log
+
+set timeout 30
+
+proc bold {} {
+  return [exec tput bold]
+}
+proc red {} {
+  return [exec tput setaf 1]
+}
+proc green {} {
+  return [exec tput setaf 2]
+}
+proc normal {} {
+  return [exec tput sgr0]
+}
+
+set bip39_mnemonic "online pipe enough dutch decorate want moment scheme rigid enlist blast boat purse sick chalk shop brush all return betray jacket salon abandon retire"
+set electrum_mnemonic "month pet slice know amused leave now vague palm guess cattle element cross truly auto put among craft repeat van sample nephew sad family"
+set failed "[bold][red]Failed[normal]"
+set ok "[bold][green]OK[normal]"
+
+puts "[bold]Should create BIP39 mnemonic[normal]"
+
+spawn qr-backup.sh --create-bip39-mnemonic
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Format USB flash drive \(y or n\)\?} {
+    send "n\r"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {\[sudo\] password for pi:} {
+    send "$env(password)\r"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Creating BIP39 mnemonic…}
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {(([a-z]+ ?){24})} {
+    exit 0
+  }
+}
+
+puts "[bold]Should validate valid BIP39 mnemonic[normal]"
+
+spawn qr-backup.sh --validate-bip39-mnemonic
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Format USB flash drive \(y or n\)\?} {
+    send "n\r"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {\[sudo\] password for pi:} {
+    send "$env(password)\r"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Please type secret and press enter, then ctrl\+d} {
+    sleep 0.1
+    send "$bip39_mnemonic\r"
+    sleep 0.1
+    send "\x04"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Please type bip39_mnemonic and press enter, then ctrl\+d \(again\)} {
+    sleep 0.1
+    send "$secret\r"
+    sleep 0.1
+    send "\x04"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Please type passphrase and press enter} {
+    puts $ok
+    exit 0
+  }
+}
+
+puts "[bold]Should fail to validate invalid BIP39 mnemonic[normal]"
+
+spawn qr-backup.sh --validate-bip39-mnemonic
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Format USB flash drive \(y or n\)\?} {
+    send "n\r"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {\[sudo\] password for pi:} {
+    send "$env(password)\r"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Please type secret and press enter, then ctrl\+d} {
+    sleep 0.1
+    send "$electrum_mnemonic\r"
+    sleep 0.1
+    send "\x04"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Please type electrum_mnemonic and press enter, then ctrl\+d \(again\)} {
+    sleep 0.1
+    send "$secret\r"
+    sleep 0.1
+    send "\x04"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Invalid BIP39 mnemonic} {
+    puts $ok
+    exit 0
+  }
+}
+
+interact
diff --git a/how-to-create-encrypted-paper-backup/tests/default.exp b/how-to-create-encrypted-paper-backup/tests/default.exp
new file mode 100644
index 0000000..2a8fc81
--- /dev/null
+++ b/how-to-create-encrypted-paper-backup/tests/default.exp
@@ -0,0 +1,214 @@
+#!/usr/bin/expect
+
+# exp_internal 1
+# log_file -noappend ~/expect.log
+
+set timeout 30
+
+proc bold {} {
+  return [exec tput bold]
+}
+proc red {} {
+  return [exec tput setaf 1]
+}
+proc green {} {
+  return [exec tput setaf 2]
+}
+proc normal {} {
+  return [exec tput sgr0]
+}
+
+set secret "foo\nbar"
+set passphrase "asdasd"
+set failed "[bold][red]Failed[normal]"
+set ok "[bold][green]OK[normal]"
+
+puts "[bold]Should backup secret[normal]"
+
+spawn qr-backup.sh
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Format USB flash drive \(y or n\)\?} {
+    sleep 0.1
+    send "y\r"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {\[sudo\] password for pi:} {
+    sleep 0.1
+    send "$env(password)\r"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {mkfs\.fat 4\.1 \(2017-01-24\)}
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Please type secret and press enter, then ctrl\+d} {
+    sleep 0.1
+    send "$secret\r"
+    sleep 0.1
+    send "\x04"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Please type secret and press enter, then ctrl\+d \(again\)} {
+    sleep 0.1
+    send "$secret\r"
+    sleep 0.1
+    send "\x04"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Please type passphrase and press enter} {
+    sleep 0.1
+    send "$passphrase\r"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Please type passphrase and press enter \(again\)} {
+    sleep 0.1
+    send "$passphrase\r"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Show passphrase \(y or n\)\?} {
+    sleep 0.1
+    send "y\r"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  $passphrase
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {SHA512 short hash: .+?([a-f0-9]{8})} {
+    set short_hash $expect_out(1,string)
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Show SHA512 hash as QR code \(y or n\)\?} {
+    sleep 0.1
+    send "n\r"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Done}
+}
+
+puts "[bold]Should restore secret[normal]"
+
+spawn qr-restore.sh --images $short_hash.jpg
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {\[sudo\] password for pi:} {
+    sleep 0.1
+    send "$env(password)\r"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Please type passphrase and press enter} {
+    sleep 0.1
+    send "$passphrase\r"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Show secret \(y or n\)\?} {
+    sleep 0.1
+    send "y\r"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Secret:\r\n((.|\r\n)+?)\r\nDone} {
+    set restored_secret $expect_out(1,string)
+  }
+}
+
+regsub -all {(\e\(B)?\e\[[0-9]*?m} $restored_secret {} restored_secret
+regsub -all {\r} $restored_secret {} restored_secret
+
+if { "$restored_secret" != "$secret" } {
+  puts $failed
+  exit 1
+} else {
+  puts $ok
+  exit 0
+}
+
+interact
diff --git a/how-to-create-encrypted-paper-backup/tests/electrum.exp b/how-to-create-encrypted-paper-backup/tests/electrum.exp
new file mode 100644
index 0000000..c104da5
--- /dev/null
+++ b/how-to-create-encrypted-paper-backup/tests/electrum.exp
@@ -0,0 +1,68 @@
+#!/usr/bin/expect
+
+# exp_internal 1
+# log_file -noappend ~/expect.log
+
+set timeout 30
+
+proc bold {} {
+  return [exec tput bold]
+}
+proc red {} {
+  return [exec tput setaf 1]
+}
+proc green {} {
+  return [exec tput setaf 2]
+}
+proc normal {} {
+  return [exec tput sgr0]
+}
+
+set passphrase "asdasd"
+set failed "[bold][red]Failed[normal]"
+set ok "[bold][green]OK[normal]"
+
+puts "[bold]Should create Electrum mnemonic[normal]"
+
+spawn qr-backup.sh --create-electrum-mnemonic
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Format USB flash drive \(y or n\)\?} {
+    send "n\r"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {\[sudo\] password for pi:} {
+    send "$env(password)\r"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Creating Electrum mnemonic…}
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {(([a-z]+ ?){24})} {
+    puts $ok
+    exit 0
+  }
+}
+
+interact
diff --git a/how-to-create-encrypted-paper-backup/tests/shamir.exp b/how-to-create-encrypted-paper-backup/tests/shamir.exp
new file mode 100644
index 0000000..ae2105b
--- /dev/null
+++ b/how-to-create-encrypted-paper-backup/tests/shamir.exp
@@ -0,0 +1,338 @@
+#!/usr/bin/expect
+
+# exp_internal 1
+# log_file -noappend ~/expect.log
+
+set timeout 30
+
+proc bold {} {
+  return [exec tput bold]
+}
+proc red {} {
+  return [exec tput setaf 1]
+}
+proc green {} {
+  return [exec tput setaf 2]
+}
+proc normal {} {
+  return [exec tput sgr0]
+}
+
+set passphrase "asdasd"
+set secret "foo\nbar"
+set failed "[bold][red]Failed[normal]"
+set ok "[bold][green]OK[normal]"
+
+puts "[bold]Should backup secret using Shamir Secret Sharing[normal]"
+
+spawn qr-backup.sh --shamir-secret-sharing
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Format USB flash drive \(y or n\)\?} {
+    sleep 0.1
+    send "y\r"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {\[sudo\] password for pi:} {
+    sleep 0.1
+    send "$env(password)\r"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {mkfs\.fat 4\.1 \(2017-01-24\)}
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Please type secret and press enter, then ctrl\+d} {
+    sleep 0.1
+    send "$secret\r"
+    sleep 0.1
+    send "\x04"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Please type secret and press enter, then ctrl\+d \(again\)} {
+    sleep 0.1
+    send "$secret\r"
+    sleep 0.1
+    send "\x04"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Please type passphrase and press enter} {
+    sleep 0.1
+    send "$passphrase\r"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Please type passphrase and press enter \(again\)} {
+    sleep 0.1
+    send "$passphrase\r"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Show passphrase \(y or n\)\?} {
+    sleep 0.1
+    send "y\r"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  $passphrase
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  {Encrypting secret share 1 of 5…}
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {SHA512 short hash: .+?([a-f0-9]{8})} {
+    set short_hash_1 $expect_out(1,string)
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Show SHA512 hash as QR code \(y or n\)\?} {
+    sleep 0.1
+    send "n\r"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  {Encrypting secret share 2 of 5…}
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {SHA512 short hash: .+?([a-f0-9]{8})} {
+    set short_hash_2 $expect_out(1,string)
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Show SHA512 hash as QR code \(y or n\)\?} {
+    sleep 0.1
+    send "n\r"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  {Encrypting secret share 3 of 5…}
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {SHA512 short hash: .+?([a-f0-9]{8})} {
+    set short_hash_3 $expect_out(1,string)
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Show SHA512 hash as QR code \(y or n\)\?} {
+    sleep 0.1
+    send "n\r"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  {Encrypting secret share 4 of 5…}
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {SHA512 short hash: .+?([a-f0-9]{8})} {
+    set short_hash_4 $expect_out(1,string)
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Show SHA512 hash as QR code \(y or n\)\?} {
+    sleep 0.1
+    send "n\r"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  {Encrypting secret share 5 of 5…}
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {SHA512 short hash: .+?([a-f0-9]{8})} {
+    set short_hash_5 $expect_out(1,string)
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Show SHA512 hash as QR code \(y or n\)\?} {
+    sleep 0.1
+    send "n\r"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Done}
+}
+
+puts "[bold]Should restore secret using Shamir Secret Sharing[normal]"
+
+spawn qr-restore.sh --images "$short_hash_1.jpg,$short_hash_2.jpg,$short_hash_5.jpg" --shamir-secret-sharing
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {\[sudo\] password for pi:} {
+    sleep 0.1
+    send "$env(password)\r"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Please type passphrase and press enter} {
+    sleep 0.1
+    send "$passphrase\r"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Show secret \(y or n\)\?} {
+    sleep 0.1
+    send "y\r"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Secret:\r\n((.|\r\n)+?)\r\nDone} {
+    set restored_secret $expect_out(1,string)
+  }
+}
+
+regsub -all {(\e\(B)?\e\[[0-9]*?m} $restored_secret {} restored_secret
+regsub -all {\r} $restored_secret {} restored_secret
+
+if { "$restored_secret" != "$secret" } {
+  puts $failed
+  exit 1
+} else {
+  puts $ok
+  exit 0
+}
+
+interact
diff --git a/how-to-create-encrypted-paper-backup/tests/shamir2of3.exp b/how-to-create-encrypted-paper-backup/tests/shamir2of3.exp
new file mode 100644
index 0000000..73d9409
--- /dev/null
+++ b/how-to-create-encrypted-paper-backup/tests/shamir2of3.exp
@@ -0,0 +1,280 @@
+#!/usr/bin/expect
+
+# exp_internal 1
+# log_file -noappend ~/expect.log
+
+set timeout 30
+
+proc bold {} {
+  return [exec tput bold]
+}
+proc red {} {
+  return [exec tput setaf 1]
+}
+proc green {} {
+  return [exec tput setaf 2]
+}
+proc normal {} {
+  return [exec tput sgr0]
+}
+
+set passphrase "asdasd"
+set secret "foo\nbar"
+set failed "[bold][red]Failed[normal]"
+set ok "[bold][green]OK[normal]"
+
+puts "[bold]Should backup secret using 2 of 3 Shamir Secret Sharing[normal]"
+
+spawn qr-backup.sh --shamir-secret-sharing --number-of-shares 3 --share-threshold 2
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Format USB flash drive \(y or n\)\?} {
+    sleep 0.1
+    send "y\r"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {\[sudo\] password for pi:} {
+    sleep 0.1
+    send "$env(password)\r"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {mkfs\.fat 4\.1 \(2017-01-24\)}
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Please type secret and press enter, then ctrl\+d} {
+    sleep 0.1
+    send "$secret\r"
+    sleep 0.1
+    send "\x04"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Please type secret and press enter, then ctrl\+d \(again\)} {
+    sleep 0.1
+    send "$secret\r"
+    sleep 0.1
+    send "\x04"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Please type passphrase and press enter} {
+    sleep 0.1
+    send "$passphrase\r"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Please type passphrase and press enter \(again\)} {
+    sleep 0.1
+    send "$passphrase\r"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Show passphrase \(y or n\)\?} {
+    sleep 0.1
+    send "y\r"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  $passphrase
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  {Encrypting secret share 1 of 3…}
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {SHA512 short hash: .+?([a-f0-9]{8})} {
+    set short_hash_1 $expect_out(1,string)
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Show SHA512 hash as QR code \(y or n\)\?} {
+    sleep 0.1
+    send "n\r"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  {Encrypting secret share 2 of 3…}
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {SHA512 short hash: .+?([a-f0-9]{8})} {
+    set short_hash_2 $expect_out(1,string)
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Show SHA512 hash as QR code \(y or n\)\?} {
+    sleep 0.1
+    send "n\r"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  {Encrypting secret share 3 of 3…}
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {SHA512 short hash: .+?([a-f0-9]{8})} {
+    set short_hash_3 $expect_out(1,string)
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Show SHA512 hash as QR code \(y or n\)\?} {
+    sleep 0.1
+    send "n\r"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Done}
+}
+
+puts "[bold]Should restore secret using 2 of 3 Shamir Secret Sharing[normal]"
+
+spawn qr-restore.sh --images "$short_hash_1.jpg,$short_hash_2.jpg" --shamir-secret-sharing --share-threshold 2
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {\[sudo\] password for pi:} {
+    sleep 0.1
+    send "$env(password)\r"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Please type passphrase and press enter} {
+    sleep 0.1
+    send "$passphrase\r"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Show secret \(y or n\)\?} {
+    sleep 0.1
+    send "y\r"
+  }
+}
+
+expect {
+  default {
+    puts $failed
+    exit 1
+  }
+  -re {Secret:\r\n((.|\r\n)+?)\r\nDone} {
+    set restored_secret $expect_out(1,string)
+  }
+}
+
+regsub -all {(\e\(B)?\e\[[0-9]*?m} $restored_secret {} restored_secret
+regsub -all {\r} $restored_secret {} restored_secret
+
+if { "$restored_secret" != "$secret" } {
+  puts $failed
+  exit 1
+} else {
+  puts $ok
+  exit 0
+}
+
+interact