passwd –stdin沒有這個參數（debian）
在RHEL/CentOS中，我們批量創建用戶時一般都會用到passwd –stdin參數，但是在debian/ubuntu下沒有這個參數：
man passwd -a, --all This option can be used only with -S and causes show status for all users. -d, --delete Delete a user's password (make it empty). This is a quick way to disable a password for an account. It will set the named account passwordless. -e, --expire Immediately expire an account's password. This in effect can force a user to change his/her password at the user's next login. -h, --help Display help message and exit. -i, --inactive INACTIVE This option is used to disable an account after the password has been expired for a number of days. After a user account has had an expired password for INACTIVE days, the user may no longer sign on to the account. -k, --keep-tokens Indicate password change should be performed only for expired authentication tokens (passwords). The user wishes to keep their non-expired tokens as before. -l, --lock Lock the password of the named account. This option disables a password by changing it to a value which matches no possible encrypted value (it adds a ′!′ at the beginning of the password). Note that this does not disable the account. The user may still be able to login using another authentication token (e.g. an SSH key). To disable the account, administrators should use usermod --expiredate 1 (this set the account's expire date to Jan 2, 1970). Users with a locked password are not allowed to change their password. -n, --mindays MIN_DAYS Set the minimum number of days between password changes to MIN_DAYS. A value of zero for this field indicates that the user may change his/her password at any time. -q, --quiet Quiet mode. -r, --repository REPOSITORY change password in REPOSITORY repository -R, --root CHROOT_DIR
Apply changes in the CHROOT_DIR directory and use the configuration files from the CHROOT_DIR directory. -S, --status Display account status information. The status information consists of 7 fields. The first field is the user's login name. The second field indicates if the user account has a locked password (L), has no password (NP), or has a usable password (P). The third field gives the date of the last password change. The next four fields are the minimum age, maximum age, warning period, and inactivity period for the password. These ages are expressed in days. -u, --unlock Unlock the password of the named account. This option re-enables a password by changing the password back to its previous value (to the value before using the -l option). -w, --warndays WARN_DAYS Set the number of days of warning before a password change is required. The WARN_DAYS option is the number of days prior to the password expiring that a user will be warned that his/her password is about to expire. -x, --maxdays MAX_DAYS Set the maximum number of days a password remains valid. After MAX_DAYS, the password is required to be changed.
解決的辦法是使用chpasswd命令，詳細的可以自行查看man手冊：
man chpasswdf
用法:
chpasswd user_name:password
可以用echo輸出指定的信息，然後管道給chpasswd命令處理，如：
echo testuser:Newpasswd|chpasswd
這樣，我的批量部署用戶腳本就是：
#!/bin/bash for u in `seq -w 16 20` do pass=`openssl rand -base64 8|cut -c 1-9` useradd tuser$u && echo "tuser$u:$pass"|chpasswd echo User:tuser$u pass:$pass >> /home/shell_dir/testdir/user.log done