apache生成证书错误unknown option in usage: x509 args

错误

[root@qiangqiang cert]# openssl x509 -req -days 365 -sha256 in atguigu.csr -signkey ca.key -out atguigu.crt
unknown option in
usage: x509 args
 -inform arg     - input format - default PEM (one of DER, NET or PEM)
 -outform arg    - output format - default PEM (one of DER, NET or PEM)

解决

openssl x509 -req -days 365 -sha256 -in atguigu.csr -signkey ca.key -out atguigu.crt

原因：原来是命令里 选项【-in】没有加横杠