最後更新: 2020-10-12

目錄

• chpasswd
• mkpasswd
• pwgen
• Troubleshoot

chpasswd

功能:

update passwords in batch mode

用發:

echo "user:pass" | chpasswd

設定 clear-text password 加密方式:

-e, --encrypted

Supplied passwords are in encrypted form.

-c, --crypt-method METHOD

Use the specified method to encrypt the passwords

(Default: /etc/login.defs "ENCRYPT_METHOD SHA512")

/etc/shadow crypt format:

$6$saltsalt$

• "$1$" => MD5
• "$5$" => SHA-1
• "$6$" => SHA-512

mkpasswd

# Centos 沒有此 Package

mkpasswd -m help

mkpasswd -m pw_method PASSWORD SALT

Available methods:

des               # standard 56 bit DES-based crypt(3)
md5
sha-256
sha-512

# 建立 sha-512 password

mkpasswd -m sha-512

#  由 string 選出 6 位 pw

makepasswd --chars=6 --count=30 --string=abcdefghijkmnpqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ23456789

pwgen

pwgen [ OPTIONS ] [ pw_length ] [ num_pw ]

OPTIONS

• -1                                                 # Print the generated passwords one per line.
• -B, --ambiguous                             # Don't use characters that could be confused by the user when printed
                                                      # ('l' and '1', or '0' or 'O')
• -c or --capitalize                            # Include at least one capital letter in the password

Usage exmaple

pwgen -B -c -1

Troubleshoot

Error

chpasswd: cannot lock /etc/passwd; try again later.

<1> 看看 '/' 是否 Full 了

df -h /

<2> 看看 '/etc' 是否 ReadOnly

touch /etc/test.txt
mount -o remount,rw /

<3> 查看有沒有 chpasswd 在行

ps aux | grep chpasswd

<4> 查看是否有 lock file

ls /etc/*.lock

rm /etc/passwd.lock
rm /etc/shadow.lock
rm /etc/group.lock
rm /etc/gshadow.lock