1、查找/etc目录下大于1M且类型为普通文件的所有文件
[root@localhost ~]# find /etc/ -type f -size +1M
/etc/selinux/targeted/active/policy.kern
/etc/selinux/targeted/contexts/files/file_contexts.bin
/etc/selinux/targeted/policy/policy.31
/etc/udev/hwdb.bin
/etc/brltty/zh-tw.ctb
[root@localhost ~]# ll /etc/udev/hwdb.bin
-r--r--r--. 1 root root 7916435 Dec 18 21:35 /etc/udev/hwdb.bin
2、打包/etc/目录下面所有conf结尾的文件，压缩包名称为当天的时间，并拷贝到/usr/local/src目录备份。
[root@localhost data]# ll
total 100
-rw-r--r--. 1 root root 101977 Dec 25 20:42 2019-12-25.tar.gz
[root@localhost data]# tar -czvf `date +%F`.tar.gz /etc/*.conf
[root@localhost data]# cp 2019-12-25.tar.gz /usr/local/src/
[root@localhost data]# ls /usr/local/src/
2019-12-25.tar.gz
[root@localhost data]#
3、利用sed 取出ifconfig命令中本机的IPv4地址
[root@localhost data]# ifconfig | sed -rn 's/^[[:space:]]+inet[[:space:]]([0-9.]+).*$/\1/p'
192.168.80.11
127.0.0.1
192.168.122.1
4、删除/etc/fstab文件中所有以#开头，后面至少跟一个空白字符的行的行首的#和空白字符
[root@localhost data]# sed -r 's/^#[[:space:]]+(.*)$/\1/' /etc/fstab
#
/etc/fstab
Created by anaconda on Wed Dec 18 21:09:21 2019
#
Accessible filesystems, by reference, are maintained under '/dev/disk'
See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
UUID=a44aa5cc-a3af-43d4-9c7d-c403035d4ea9 / xfs defaults 0 0
UUID=2998e3c4-91ec-4f14-b19e-52e1640f2780 /boot xfs defaults 0 0
UUID=ad28f936-2450-4a37-8660-e97ca35380a1 /data xfs defaults 0 0
UUID=eba4d637-f817-4e13-918d-f9f812022472 swap swap defaults
5、处理/etc/fstab路径,使用sed命令取出其目录名和基名
[root@localhost data]# echo /etc/fstab | sed -r 's@^(/[[:alpha:]]+/)(.*)$@\1@'
/etc/
[root@localhost data]# echo /etc/fstab | sed -r 's@^(/[[:alpha:]]+/)(.*)$@\2@'
fstab
[root@localhost data]#
