练习
1、显示当前时间，格式：2016-06-18 10:20:30
2、显示前天是星期几
3、设置当前日期为2019-08-07 06:05:10
答：1、[root@centos6 ~]#date "+%F %T"
2018-12-15 01:12:29
2、[root@centos6 ~]#date -d "-2 day" +%w
4
3、[root@centos6 ~]#date -s "2019-08-07 06:05:10" "+%F %T"
2019-08-07 06:05:10
=================分割线===================
练习：
*1：在本机字符终端登录时，除显示原有信息外，再显示当前登录终端号，主机名和当前时 间
*2：今天18：30自动关机，并提示用户
答：1、[root@centos7 ~]#> /etc/profile.d/env.sh
[root@centos7 ~]#nano /etc/profile.d/env.sh
PS1="\[\e[1;35m\][\u@\l \H \w \t]\\$\[\e[0m\]"
[root@centos7 ~]#. /etc/profile.d/env.sh
[root@1 centos7 ~ 12:38:41]#
2、[root@1 centos7 ~ 12:38:51]#shutdown -h 18:30 the OS will be shutdown at 18:30
Shutdown scheduled for Mon 2018-12-17 18:30:00 CST, use 'shutdown -c' to cancel.
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练习
1、显示/var目录下所有以l开头，以一个小写字母结尾，且中间出现至少一位数字的文件或目录
2、显示/etc目录下以任意一位数字开头，且以非数字结尾的文件或目录
3、显示/etc/目录下以非字母开头，后面跟了一个字母及其它任意长度任意字符的文件或目录
4、显示/etc/目录下所有以rc开头，并后面是0-6之间的数字，其它为任意字符的文件或目录
5、显示/etc目录下，所有以.d结尾的文件或目录
6、显示/etc目录下，所有.conf结尾，且以m,n,r,p开头的文件或目录
7、只显示/root下的隐藏文件和目录
8、只显示/etc下的非隐藏目录
答：1、[root@centos7 ~]#ls /var/l*[0-9]*[[:lower:]]
/var/l23xp /var/la99la /var/ll23xp
2、[root@centos7 ~]#ls -d /etc/[0-9]*[^0-9]
/etc/22la99la /etc/2la99la
3、[root@centos7 ~]#ls -d /etc/[^a-Z][a-Z]*
/etc/2la99la
或者[root@centos7 ~]#ls -d /etc/[^[:alpha:]][[:alpha:]]*
/etc/2la99la
4、[root@centos7 ~]#ls -d /etc/rc[0-6]*
/etc/rc0.d /etc/rc1.d /etc/rc2.d /etc/rc3.d /etc/rc4.d /etc/rc5.d /etc/rc6.d
5、[root@centos7 ~]# ls -d /etc/*.d
/etc/bash_completion.d /etc/ipsec.d /etc/prelink.conf.d /etc/rsyslog.d
/etc/binfmt.d /etc/krb5.conf.d /etc/profile.d /etc/rwtab.d
/etc/chkconfig.d /etc/ld.so.conf.d /etc/rc0.d /etc/sane.d
/etc/cron.d /etc/libibverbs.d /etc/rc1.d /etc/setuptool.d
/etc/depmod.d /etc/logrotate.d /etc/rc2.d /etc/statetab.d
/etc/dnsmasq.d /etc/modprobe.d /etc/rc3.d /etc/sudoers.d
/etc/dracut.conf.d /etc/modules-load.d /etc/rc4.d /etc/sysctl.d
/etc/exports.d /etc/my.cnf.d /etc/rc5.d /etc/tmpfiles.d
/etc/gdbinit.d /etc/oddjobd.conf.d /etc/rc6.d /etc/xinetd.d
/etc/grub.d /etc/pam.d /etc/rc.d /etc/yum.repos.d
/etc/init.d /etc/popt.d /etc/request-key.d
6、[root@centos7 ~]#ls /etc/[mnrp]*.conf
/etc/man_db.conf /etc/nfsmount.conf /etc/pnm2ppa.conf /etc/rsyncd.conf
/etc/mke2fs.conf /etc/nsswitch.conf /etc/radvd.conf /etc/rsyslog.conf
/etc/mtools.conf /etc/numad.conf /etc/request-key.conf
/etc/nfs.conf /etc/pbm2ppa.conf /etc/resolv.conf
7、[root@centos7 ~]#ls -d /root/.*
/root/. /root/.bash_profile /root/.cshrc /root/.lesshst
/root/.. /root/.bashrc /root/.dbus /root/.local
/root/.bash_history /root/.cache /root/.esd_auth /root/.tcshrc
/root/.bash_logout /root/.config /root/.ICEauthority /root/.viminfo
8、[root@centos7 ~]#ls -d /etc/*/
/etc/abrt/ /etc/iproute2/ /etc/rc1.d/
/etc/alsa/ /etc/ipsec.d/ /etc/rc2.d/
/etc/alternatives/ /etc/iscsi/ /etc/rc3.d/
/etc/audisp/ /etc/java/ /etc/rc4.d/
/etc/audit/ /etc/jvm/ /etc/rc5.d/
/etc/avahi/ /etc/jvm-commmon/ /etc/rc6.d/
/etc/bash_completion.d/ /etc/kernel/ /etc/rc.d/
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练习
1、定义别名命令baketc，每天将/etc/目录下所有文件，备份到/data独立的子目录下，并要求子目录格式为 backupYYYY-mm-dd，备份过程可见
2、创建/data/rootdir目录，并复制/root下所有文件到该目录内，要求保留原有权限
答：1、[root@centos7 ~]#alias baketc='\cp -rfv /etc /data/backup`date +%F`'
[root@centos7 ~]#baketc
...... #此行是可见的备份过程
[root@centos7 ~]#ls /data
backup2018-12-17
2、[root@centos7 ~]#mkdir -p /data/rootdir/
[root@centos7 ~]#\cp -a /root/* /data/rootdir/
[root@centos7 ~]#ls /data
backup2018-12-17 rootdir
[root@centos7 ~]#ls /root
anaconda-ks.cfg Documents initial-setup-ks.cfg Pictures Templates 老铁
Desktop Downloads Music Public Videos
[root@centos7 ~]#ls /data/rootdir/
anaconda-ks.cfg Documents initial-setup-ks.cfg Pictures Templates 老铁
Desktop Downloads Music Public Videos