Saturday, May 3, 2025
Friday, November 3, 2023
Centos 7 reset root/ any user lost password / lockout due to cant remember password
- find the line that load the kernel - begins with 'linux16' in my case.
- find text "rhgb quiet" , replace it with "rd.break enforcing=0".
- When done. Press Ctrl X. The system will boot with the parameter edited.
- remount the root filesystem. "# mount -o remount,rw /sysroot"
- set the environment to /sysroot "# chroot /sysroot/"
- change desired password. root/any other user. "# passwd root"
- when done. remount / to readonly back "# mount -o remount, ro /"
- Then "# exit".
- Then "# exit" again. system continue to boot.
- login as root with the newly created password. DO NOT REBOOT YET.
- SELinux will detect that the password file /etc/shadow has been changed and will restrict access to it). Instead, you must first restore the SELinux labels on that file:
- "# restorecon /etc/shadow".
- Then reboot
Thursday, June 17, 2021
mysql_upgrade return error "Can't get stat of './mysql/general_log.CSV"
ERROR 13 (HY000) at line 286: Can't get stat of './mysql/general_log.CSV' (Errcode: 2 "No such file or directory")
ERROR 13 (HY000) at line 297: Can't get stat of './mysql/slow_log.CSV' (Errcode: 2 "No such file or directory")
ERROR 13 (HY000) at line 299: Can't get stat of './mysql/slow_log.CSV' (Errcode: 2 "No such file or directory")
ERROR 13 (HY000) at line 301: Can't get stat of './mysql/slow_log.CSV' (Errcode: 2 "No such file or directory")
FATAL ERROR: Upgrade failed
This is very strange that general_log.CSV and slow_log.CSV did not exist, do you know how it happened? Did somebody remove them manually?
Did general_log.frm and slow_log.frm files exist?
The most likely reason for the problem is that due to the disappearance of CSV files, the tables were left in an inconsistent state.
You can try to do the following:
# Make sure there are no remains of the table |
- rm ./mysql/general_log.* ./mysql/slow_log.* |
# connect to the server and run |
[MariaDB]> FLUSH TABLES; |
# Then re-run |
mysql_upgrade -uroot -p --force
|
It should work unless somebody previously tried to convert general_log and slow_log tables into InnoDB, in this case things can be a bit more complicated.
Wednesday, November 25, 2020
Apache get concurrent connection
Reference: https://www.cloudtechtiq.com/blog/check-apache-concurrent-connections-using-netstat-command
To Count Apache concurrent connection's, use any of the below commands.
netstat -nt | grep :80 | wc -l netstat -plan|grep :80 | wc -l netstat -an | grep 'EST' | wc -l netstat -ant | grep ESTABLISHED | grep :80 | wc -l ps -A | grep httpd | wc -l ps -ef | grep http | wc -l ps aux | grep httpd | wc -l ps aux | grep http | grep -v "\(root\|grep\)" | wc -lTo print the active Internet connections to the server at port 80 and sort the results, use the below commands.
netstat -an | grep :80 | sort netstat -plan | grep :80 netstat -anp | grep :80To calculate and count, number of connection currently established from each IP address with server.
netstat -ntu | awk '{print $5}' | cut -d: -f1 | sort | uniq -c | sort -nTo calculate and count, number of connection currently established from each IP address through TCP or UDP protocol with server.
netstat -anp |grep 'tcp\|udp' | awk '{print $5}' | cut -d: -f1 | sort | uniq -c | sort -nTo Print ESTABLISHED connections instead of all connections, and displays the connections count for each IP
netstat -ntu | grep ESTAB | awk '{print $5}' | cut -d: -f1 | sort | uniq -c | sort -nrTo print the list of IP address and its connection count, that connect to port 80 on the server.
netstat -plan|grep :80|awk {'print $5'}|cut -d: -f 1|sort|uniq -c|sort -nk 1To print all the apache httpd actual processes in Linux, use the below commands.
ps -aux | grep httpd or ps -ef | grep httpdSunday, August 30, 2020
mysqldump comparison using compress option with bzip2 and gzip performance and the output size
Monday, December 9, 2019
Tuesday, December 3, 2019
Show hidden files and sub directories in root directory
By default the root directory will not show you the directories like /usr, /bin, /etc etc. To make them visible you need to show the hidden files.
Open terminal and type the following command and hit return.
defaults write com.apple.finder AppleShowAllFiles -bool TRUE;killall Finder
Reference: https://themacbeginner.com/view-content-root-directory-mac-os-x/
Tuesday, July 9, 2019
Wednesday, March 27, 2019
Saturday, December 29, 2018
Mysql On delete cascade reference information
Tips to find tables affected by MySQL ON DELETE CASCADE action
Sometimes, it is useful to know which table is affected by the MySQL ON DELETE CASCADE referential action when you delete data from a table. You can query this data from the referential_constraints in the information_schema database as follows:
1 2 3 4 5 6 7 8 9 10 | USE information_schema; SELECT table_name FROM referential_constraints WHERE constraint_schema = 'database_name' AND referenced_table_name = 'parent_table' AND delete_rule = 'CASCADE' |
Thursday, November 29, 2018
mariadb @ mysql change datadir to /home/ directory
Wednesday, June 27, 2018
Troubleshooting “Permission denied” when attempting to connect to Redis from PHP script
Problem solved, type:
/usr/sbin/setsebool httpd_can_network_connect=1By default, SELinux does not allow Apache to make socket connections. More information can be found here.
source: https://stackoverflow.com/questions/8765848/troubleshooting-permission-denied-when-attempting-to-connect-to-redis-from-phpTuesday, June 26, 2018
PHP / CentOS 7Connect DATABASE Error TYPE: 2002: Permission denied
I had the same issue after getting a new CentOS 7 box, running SELinux. I could connect to my remote MySQL DB server from the command line, but Drupal (and test PHP scripts) could not.
The issue turned out to be the SELinux security policies.
By default, the policy httpd_can_network_connect_db is disabled (meaning that your web server cannot contact a remote DB.)
Check this via:
getsebool -a | grep httpd
If httpd_can_network_connect_db is Off, enable it via:
setsebool -P httpd_can_network_connect_db 1(The -P flag makes the change permanent, so the setting survives a reboot.)
Nginx php html permission denied
After searching , I found it.It's all deals with SELINUX which is a security feature. when using ls -Z
drwxrwxrwx. ec2-user root system_u:object_r:httpd_sys_content_t:s0 wwwchange this to
drwxrwxrwx. ec2-user root system_u:object_r:httpd_sys_rw_content_t:s0 wwwusing cmd
chcon -R -t httpd_sys_rw_content_t /var/www Tuesday, July 18, 2017
Thursday, July 13, 2017
Sublime Text Licence
-----Begin----------
TwitterInc
200 User License
EA7E-890007
1D77F72E 390CDD93 4DCBA022 FAF60790
61AA12C0 A37081C5 D0316412 4584D136
94D7F7D4 95BC8C1C 527DA828 560BB037
D1EDDD8C AE7B379F 50C9D69D B35179EF
2FE898C4 8E4277A8 555CE714 E1FB0E43
D5D52613 C3D12E98 BC49967F 7652EED2
9D2D2E61 67610860 6D338B72 5CF95C69
E36B85CC 84991F19 7575D828 470A92AB
----------End---------
Tuesday, November 1, 2016
Git delete merged remote branch
git branch -r --merged origin/master | grep origin | grep -v '>' | grep -v master | awk '{sub(/origin\//,"");print}'| xargs git push origin --delete
Saturday, October 1, 2016
phpstorm 2016.2
Sunday, September 25, 2016
window 8.1 product key
| Windows 8.1 Single Language |
|
Proxmox installation display out of range
Reference: https://forum.proxmox.com/threads/proxmox-ve-screen-out-of-range.131297/
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Original Source :: http://en.irfanview-forum.de/viewtopic.php?t=490 /one - force 'Only one instance' /fs - force Full Screen displa...
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Original Source:: http://www.zytrax.com/tech/pc/serial.html Tech Info - USB and Firewire USB and FireWire (IEEE 1394a and b) represent the...

