Category: Linux Command

How to update/install glibc-2.14 on centos 6.x

Update reason:

Shell
1
.../node_modules/webp-converter/lib/libwebp_linux/bin/dwebp: /lib64/libc.so.6: version `GLIBC_2.14' not found

  check installed glibc version:

Shell
1
2
[[email protected] lib64]# ldd --version
ldd (GNU libc) 2.12

  I have tried update glibc like below:

Shell
1
yum update glibc

but didn’t work, so tried the solution like below steps: download glibc-2.14.tar.gz extract the download files and build, install in /opt/glibc-2.14:

Shell
1
2
3
4
5
6
7
[[email protected] ~]#tar -xzvf glibc-2.14.tar.gz
[[email protected] ~]#cd glibc-2.14
[[email protected] glibc-2.14]# mkdir build
[[email protected] glibc-2.14]# cd build
[[email protected] build]# ../configure --prefix=/opt/glibc-2.14
[[email protected] build]# make -j4
[[email protected] build]# make install

  update glibc symbolic links:

Shell
1
2
[[email protected] lib64]rm -rf /lib64/libc.so.6
[[email protected] lib64]LD_PRELOAD=/opt/glibc-2.14/lib/libc-2.14.so  ln -s /opt/glibc-2.14/lib/libc-2.14.so /lib64/libc.so.6

  If you want restore glibc symbolic links :

Shell
1
2
[[email protected] lib64]rm -rf /lib64/libc.so.6
[[email protected] lib64]$ LD_PRELOAD=/lib64/libc-2.12.so ln -s /lib64/libc-2.12.so /lib64/libc.so.6

 

Bookmark/Favorites

How to find files created on a specific date?

1.How to find files modified / created /  accessed  on a specific date Example 1: find files modified on the 10th of December

find files modified on the 10th of December
Shell
1
$ find . -type f -newermt 2018-12-10 ! -newermt 2018-12-11

Example 2: find files created on the 10th of December

find files created on the 10th of December
Shell
1
$ find . -type f -newerct 2018-12-10 ! -newerct 2018-12-11

Example 3: find files accessed on the 10th of December

find files accessed on the 10th of December
Shell
1
$ find . -type f -newerat 2018-12-10 ! -newerat 2018-12-11

  2.Then how to use find to delete the files found above

Shell
1
 find . -type f -newermt 2018-12-10 ! -newermt 2018-12-11 -exec rm -rf {} \;

[…]

Bookmark/Favorites

How to use iptables to defend against reflection DDOS attack on Centos

Usually use iptables to drop the UDP fragmented packets, below is the iptables config example: vi /etc/sysconfig/iptables

Shell
1
2
3
4
-A INPUT -i eth1 -p udp -m udp -m multiport --dports 19,53,111,123,161,1121,1900 -j DROP
-A INPUT -i eth1 -p udp -m udp -m multiport --sports 19,53,111,123,161,1121,1900 -j DROP
-A OUTPUT -o eth1 -p udp -m udp -m multiport --dports 19,53,111,123,161,1121,1900 -j DROP
-A OUTPUT -o eth1 -p udp -m udp -m multiport --sports 19,53,111,123,161,1121,1900 -j DROP

  Reference: 1 HOW TO DEFEND AGAINST AMPLIFIED REFLECTION DDOS ATTACKS 2 DDoS attacks – an explanation of amplified reflective UDP-based attacks

Bookmark/Favorites

How to disable DST (Daylight Saving Time) in Linux

As you know, Europe area has daylight saving time (summer time). DST will change the Linux server’s time automatically, so some system will become stranger under DST. Here is an example to change Europe/London time to UTC time (because there is no DST in UTC time) to disable the DST. Confirm the system date

Shell
1
2
[root@ ~]$ date
Thu Apr  2 05:37:35 BST 2015

  […]

Bookmark/Favorites