黑龙江快乐十分

test -n/-z的注意事项

2/13/2017来源:经验技巧人气:17809

黑龙江快乐十分youshihuiyongdao-n -zlaipanduanzifuchuanzhangdu,yongdaobianliangshiyaoxiaoxin。bijiaoyixialiangtiaoyuju

黑龙江快乐十分[monitor@msg7 .monitor]$ if [ -n $b ];then echo yes;else echo no;fi
yes
[monitor@msg7 .monitor]$ if [ -n "$b" ];then echo yes;else echo no;fi
no
$bshiweidingyiyigedebianliang,danshiyouyinhaohemeiyinhao,-njichulebutongdedaan。suoyiyaojidejiayinhao,cainengzhengqueshibiezifuchuanbianliangdezhangdu。



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