Pipe or echo password into RAR command?

Question

I'm trying to use RAR from the command line on a password protected archive:

$ rar t spe_05_1.part13.rar

RAR 5.11   Copyright (c) 1993-2014 Alexander Roshal   27 Aug 2014
Trial version             Type RAR -? for help

Enter password (will not be echoed) for spe_05_1.part13.rar: 

RAR does not appear to have a password switch. It does offer a way to set a password on an archive, but I can't find a way to pass the password to the command for testing (t command) or extraction (x command):

$ rar | grep -i password
  hp[password]  Encrypt both file data and headers
  p[password]   Set password
  p-            Do not query password

I need to automate entering the password (I have to try multiple passwords), so I am trying to use echo and pipe:

$ echo diespe120 | rar t spe_05_1.part13.rar

RAR 5.11   Copyright (c) 1993-2014 Alexander Roshal   27 Aug 2014
Trial version             Type RAR -? for help

Enter password (will not be echoed) for spe_05_1.part13.rar: 

Unfortunately, that's prompting me.

How do I automate entering a password for RAR in a script?

---

PASSWORDS=
for i in {100..150}
do
    pw=$(printf "diespe%03d" $i)
    PASSWORDS+="$pw " 
done

for PASSWORD in $PASSWORDS
do
    echo $PASSWORD | rar t spe_05_1.part13.rar
    if [ $? -eq 0 ]; then
        echo "Password is " $PASSWORD
        break
    fi
done

Answer 1

How do I automate entering a password for RAR in a script?

To automate, don't use a pipe. Use a shell variable instead. Try:

for PASSWORD in $PASSWORDS
do
    rar t -p"$PASSWORD" spe_05_1.part13.rar
    if [ $? -eq 0 ]; then
        echo "Password is '$PASSWORD'"
        break
    fi
done