Arch Loop项目中如何无交互创建用户并设置密码？

Hey there! I feel your pain—repeating the Arch install process multiple times a day is such a drain, so automating it makes total sense. Let's figure out why your password setup trick is failing for TTY logins, and fix it with a reliable, non-interactive method.

Why Your Original Approach Isn't Working #

The echo -e 'password\npassword\n' | passwd method can flake out in chroot environments because:

• Some versions of passwd enforce TTY input checks (even when wrapped in bash -c), which can silently fail to set the password correctly.
• The -e flag for echo might behave differently in the chroot's shell environment, leading to malformed input that doesn't match what you expect.

You were on the right track with pre-encrypting passwords—this is the most reliable way to avoid interactive prompts entirely.

The Proper Non-Interactive Solution #

We'll use crypt-format password hashes (which is what /etc/shadow stores) to set passwords directly, no passwd command hoops required. Here's how to implement it:

1. Safely Collect User Passwords

First, read passwords securely without echoing them to the terminal:

# Read non-root user details
read -r -p "Enter non-root username: " USERNAME
read -r -s -p "Enter $USERNAME password: " USER_PASSWORD
echo
read -r -s -p "Confirm $USERNAME password: " USER_PASSWORD_CONFIRM
echo
if [ "$USER_PASSWORD" != "$USER_PASSWORD_CONFIRM" ]; then
    echo "Error: Passwords don't match!"
    exit 1
fi

# Read root password
read -r -s -p "Enter root password: " ROOT_PASSWORD
echo
read -r -s -p "Confirm root password: " ROOT_PASSWORD_CONFIRM
echo
if [ "$ROOT_PASSWORD" != "$ROOT_PASSWORD_CONFIRM" ]; then
    echo "Error: Root passwords don't match!"
    exit 1
fi

2. Generate Encrypted Password Hashes

Use openssl (pre-installed on Arch install media) to generate SHA-512 hashes with random salts—this is secure and compliant with Arch's shadow file standards:

USER_ENCRYPTED=$(openssl passwd -6 "$USER_PASSWORD")
ROOT_ENCRYPTED=$(openssl passwd -6 "$ROOT_PASSWORD")

The -6 flag specifies SHA-512, which is the default for Arch Linux.

3. Set Passwords in Chroot

Now apply these hashes directly to the user accounts:

# Create non-root user with pre-hashed password
arch-chroot /mnt useradd -m -g users -G wheel -s /usr/bin/bash -p "$USER_ENCRYPTED" "$USERNAME"

# Set root password using chpasswd (handles shadow file updates cleanly)
arch-chroot /mnt bash -c "echo root:$ROOT_ENCRYPTED | chpasswd -e"

• The -p flag for useradd accepts the pre-encrypted hash directly.
• chpasswd -e tells the command we're passing encrypted hashes instead of plaintext.

4. Optional: Configure Sudo Access

If you haven't already, make sure the wheel group can use sudo:

arch-chroot /mnt sed -i 's/^# %wheel ALL=(ALL:ALL) ALL/%wheel ALL=(ALL:ALL) ALL/' /etc/sudoers

Why This Works #

This method bypasses the interactive passwd command entirely, writing directly to the /etc/shadow file through trusted tools. It avoids TTY checks, shell inconsistencies, and ensures your passwords are stored securely with proper hashing.

内容的提问来源于stack exchange，提问作者Vasanth Srivatsa