今天看到了馬哥的視頻，講道理passwd命令和管道的標準輸入時，一個命令重置密碼。
我測試了一下報錯
echo "test" | password --stdin test
root@localhost:/home/test2# echo "test" | password --stdin test
未找到 'password' 命令，您要輸入的是否是：
命令 'assword' 來自於包 'assword' (universe)
password：未找到命令
root@localhost:/home/test2# echo "test" | passwd --stdin test
passwd：無法識別的選項“--stdin”
Usage: passwd [options] [LOGIN]
Options:
-a, --all report password status on all accounts
-d, --delete delete the password for the named account
-e, --expire force expire the password for the named account
-h, --help display this help message and exit
-k, --keep-tokens change password only if expired
-i, --inactive INACTIVE set password inactive after expiration
to INACTIVE
-l, --lock lock the password of the named account
-n, --mindays MIN_DAYS set minimum number of days before password
change to MIN_DAYS
-q, --quiet quiet mode
-r, --repository REPOSITORY change password in REPOSITORY repository
-R, --root CHROOT_DIR directory to chroot into
-S, --status report password status on the named account
-u, --unlock unlock the password of the named account
-w, --warndays WARN_DAYS set expiration warning days to WARN_DAYS
-x, --maxdays MAX_DAYS set maximum number of days before password
change to MAX_DAYS
我看到這個錯誤，我以爲是passwd --stdin這個參數問題，於是我上網百度了一下，大家都說沒問題啊，
意外在Ubuntu論壇中發現了一個帖子
最近學習鳥哥的passwd用法時練習建立賬號並修改密碼（密碼統一爲“password”），程序如下
#!/bin/bash
groupadd myquotagrp
for username in myquota1 myquota2 myquota3 myquota4 quota5
do
useradd -g myquotagrp $username
echo "password" | passwd --stdin $username
done
運行後報錯
passwd: unrecognized option '--stdin'
Usage: passwd [options] [LOGIN]
Options:
-a, --all report password status on all accounts
-d, --delete delete the password for the named account
-e, --expire force expire the password for the named account
-h, --help display this help message and exit
-k, --keep-tokens change password only if expired
-i, --inactive INACTIVE set password inactive after expiration
to INACTIVE
-l, --lock lock the password of the named account
-n, --mindays MIN_DAYS set minimum number of days before password
change to MIN_DAYS
-q, --quiet quiet mode
-r, --repository REPOSITORY change password in REPOSITORY repository
-S, --status report password status on the named account
-u, --unlock unlock the password of the named account
-w, --warndays WARN_DAYS set expiration warning days to WARN_DAYS
-x, --maxdays MAX_DAYS set maximim number of days before password
change to MAX_DAYS
我又查了下passwd的用法，雖然不是很懂，但嘗試了openssl passwd -stdin
還是報錯：
Usage: passwd [options] [passwords]
where options are
-crypt standard Unix password algorithm (default)
-1 MD5-based password algorithm
-apr1 MD5-based password algorithm, Apache variant
-salt string use provided salt
-in file read passwords from file
-stdin read passwords from stdin
-noverify never verify when reading password from terminal
-quiet no warnings
-table format output as table
-reverse switch table columns
最後看到了其中一個信息
passwd的--stdin參數ubuntu不支持，其實debian就不支持這個，自己後來在centos7中測試了一下，可以，原理問題就出在這裏。
因爲我的系統是Ubuntu14.04的系統，終於找到問題的原因了。
後來在網上找到了一個方法就是換行，模擬兩次輸入密碼，但是發現還是不行，
root@localhost:/home/test2# echo "test\ntest" | passwd test2
輸入新的 UNIX 密碼： 重新輸入新的 UNIX 密碼： passwd: 認證令牌操作錯誤
passwd: password unchanged
自己直接重置密碼可以。
root@localhost:/home/test2# passwd test2
輸入新的 UNIX 密碼：
重新輸入新的 UNIX 密碼：
passwd: password updated successfully
root@localhost:/home/test2#
自己想到這裏也沒有好的辦法了，希望高手也可以留言，幫忙解決一下吧