；举例
[root@andon ~]# date;dd if=/dev/zero  of=/home/1  bs=1k count=10240;date  ##统计dd命令消耗时间，其中/dev/zero为空文件

Tue Jun 14 15:15:02 CST 2016

10240+0 records in

10240+0 records out

10485760 bytes (10 MB) copied, 0.0224696 s, 467 MB/s

Tue Jun 14 15:15:02 CST 2016

&&举例

[root@andon ~]# ls &&echo yes

1  anaconda-ks.cfg  install.log  install.log.syslog  shell

yes

[root@andon ~]# lss &&echo yes

-bash: lss: command not found

||举例

[root@andon ~]# ls || echo yes

1  anaconda-ks.cfg  install.log  install.log.syslog  shell

[root@andon ~]# lsd || echo yes

-bash: lsd: command not found

yes