长度为32位 [root@harbor ~]# echo $RANDOM | sha256sum | base64 | head -c 32; echo MTY1YTAxYzNmMGFmMmI5ZGEyYTMxNzk2 [root@harbor ~]# tr -cd "1-39" < /dev/urandom | head -c 32 93211212323391391213232112222212You have new mail in /var/spool/mail/root [root@harbor ~]#
原文：https://www.cnblogs.com/wyf-577513827/p/11428009.html