Linux学习第五周

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一、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 | xargs ls -lh
-rw-------. 1 root root 3.8M Nov  3  2018 /etc/selinux/targeted/active/policy.kern
-rw-r--r--. 1 root root 1.4M Nov  3  2018 /etc/selinux/targeted/contexts/files/file_contexts.bin
-rw-r--r--. 1 root root 3.8M Nov  3  2018 /etc/selinux/targeted/policy/policy.31
-r--r--r--. 1 root root 7.6M Jun  9 20:38 /etc/udev/hwdb.bin

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二、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 ~]# find /etc -type f -name "*.conf" | xargs tar zcf `date +%F`.tar.gz && cp `date +%F`.tar.gz /usr/local/src
tar: Removing leading `/' from member names
[root@localhost ~]# ls
111  192.168.1.111  1.txt  2020-07-07.tar.gz  2.txt  3.txt  aaa  abc.php  anaconda-ks.cfg  bbb  creatuser.sh  test1  test.php  test.txt
[root@localhost ~]# ls /usr/local/src
2020-07-07.tar.gz
[root@localhost ~]# date
Tue Jul  7 13:18:06 CST 2020

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三、利用sed 取出ifconfig命令中本机的IPv4地址；

[root@localhost ~]# ifconfig ens33
ens33: flags=4163  mtu 1500
        inet 192.168.1.103  netmask 255.255.255.0  broadcast 192.168.1.255
        inet6 fe80::de8:e705:819:cec0  prefixlen 64  scopeid 0x20
        ether 00:0c:29:46:a3:d9  txqueuelen 1000  (Ethernet)
        RX packets 1369  bytes 131434 (128.3 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 746  bytes 93910 (91.7 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

[root@localhost ~]# ifconfig ens33 | sed -n '2p'
        inet 192.168.1.103  netmask 255.255.255.0  broadcast 192.168.1.255
[root@localhost ~]# ifconfig ens33 | sed -n '2p' | sed -nr 's@^[^0-9]+([0-9.]+).*$@\1@p'
192.168.1.103

或者

[root@localhost ~]# ifconfig ens33 | sed -nr '2s@^[^0-9]+([0-9.]+).*$@\1@p'
192.168.1.103

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四、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；

1、备份到/tmp目录，先使用sed，将所需要匹配的行匹配出来；

[root@localhost ~]# cp /etc/fstab /tmp/
[root@localhost ~]# ll /tmp
total 4
-rw-r--r-- 1 root root   0 Jun 18 19:43 3.txt
-rw-r--r-- 1 root root 465 Jul  7 13:33 fstab
drwxr-xr-x 3 root root  17 Jun 25 10:08 mytest1
[root@localhost ~]# cat /tmp/fstab

#
# /etc/fstab
# Created by anaconda on Tue Jun  9 20:29:14 2020
#
# 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
#
/dev/mapper/centos-root /                       xfs     defaults        0 0
UUID=61bfe580-8947-41c1-91c0-0e3422e7d468 /boot                   xfs     defaults        0 0
/dev/mapper/centos-swap swap                    swap    defaults        0 0
[root@localhost ~]# sed -nr '/^#[[:blank:]]+/s@^#[[:blank:]]+(,*)@\1@p' /tmp/fstab
/etc/fstab
Created by anaconda on Tue Jun  9 20:29:14 2020
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

2、加上-i将其修改对应的文件，然后验证；

[root@localhost ~]# sed -ri '/^#[[:blank:]]+/s@^#[[:blank:]]+(,*)@\1@p' /tmp/fstab
[root@localhost ~]# cat /tmp/fstab

#
/etc/fstab
/etc/fstab
Created by anaconda on Tue Jun  9 20:29:14 2020
Created by anaconda on Tue Jun  9 20:29:14 2020
#
Accessible filesystems, by reference, are maintained under '/dev/disk'
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
See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
/dev/mapper/centos-root /                       xfs     defaults        0 0
UUID=61bfe580-8947-41c1-91c0-0e3422e7d468 /boot                   xfs     defaults        0 0
/dev/mapper/centos-swap swap                    swap    defaults        0 0

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五、处理/etc/fstab路径,使用sed命令取出其目录名和基名；

[root@localhost ~]# echo "/etc/fstab" | sed -r 's@(.*)\/.+@\1@'
/etc
[root@localhost ~]# echo "/etc/fstab" | sed -r 's@.*\/(.+)@\1@'
fstab

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