If you just want to add one user at a time as root, just separate the steps:

# useradd joe
# passwd joe
New Password: *****
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But you're asking about the way to automate it.

The /etc/shadow file takes multiple hashing formats for passwords. (Encryption is a misnomer; encryption can be reversed but hashing cannot.) There's crypt() as you've tried, and there's MD5 and a few other hashing functions. The system knows the difference based on the first couple characters. (You didn't cut and paste your shadow example literally, since your crypt() function would not have begun with a '$1'.)

Although you can get such hashes from the command line:

# openssl passwd -salt '$1' 'mypassword'
$1XahR1gy5QBc
# openssl passwd -apr1 -salt '$1' 'mypasswd'
$apr1$$1$WU93LWav20QAwX/j3i0CW/
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I hope other monks can discuss what's necessary for a script to use a module (maybe Digest::MD5) to properly hash and encode the type and hash for /etc/shadow.

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