[root@arbiter nginx]# /usr/local/nginx/sbin/nginx -t -c /usr/local/nginx/conf/nginx.conf
nginx: the configuration file /usr/local/nginx/conf/nginx.conf syntax is ok
nginx: configuration file /usr/local/nginx/conf/nginx.conf test is successful
[root@arbiter nginx]# echo $?
0

[root@arbiter nginx]# /usr/local/nginx/sbin/nginx -t -c /usr/local/nginx/conf/mime.types
nginx: [emerg] "types" directive is not allowed here in /usr/local/nginx/conf/mime.types:2
nginx: configuration file /usr/local/nginx/conf/mime.types test failed
[root@arbiter nginx]# echo $?
1

bash 中 $? 用來取得上一條指令的回傳值，0 為正常，其他值為異常。

如果需要取得命令輸出，可以按一下方式操作：

[root@arbiter nginx]# a="`/usr/local/nginx/sbin/nginx -t -c /usr/local/nginx/conf/mime.types 2>&1`"
[root@arbiter nginx]# echo $a
nginx: [emerg] "types" directive is not allowed here in /usr/local/nginx/conf/mime.types:2 nginx: configuration file /usr/local/nginx/conf/mime.types test failed

其中2>&1的作用是將標準誤差重新導向到標準輸出