Enable Jail Shell using Command in cPanel

To setup jailshell access for a user from the command line interface, simply use the operating system's change shell command as root :

# chsh -s /usr/local/cpanel/bin/jailshell ${username}

Username = cPanel username 

Show the inode usage for folders within your working directory

Following command will list complete inode usage from different folders with in the present working directory:

echo "Detailed Inode usage for: $(pwd)" ; for d in `find -maxdepth 1 -type d |cut -d\/ -f2 |grep -xv . |sort`; do c=$(find $d |wc -l) ; printf "$c\t\t- $d\n" ; done ; printf "Total: \t\t$(find $(pwd) | wc -l)\n"

Limiting number of HTTP Connections Per IP/Host

You can limit number of HTTP connections from single IP or Host using IPTABLES

The syntax is as follows :

/sbin/iptables -A INPUT -p tcp --syn --dport $port -m connlimit --connlimit-above N -j REJECT --reject-with tcp-reset

Example:

/sbin/iptables -A INPUT -p tcp --syn --dport 80 -m connlimit --connlimit-above 20 -j REJECT --reject-with tcp-reset

Above command will limit 20 HTTP connections per IP

Data error in File Manager

When you click on the File Manager in cPanel you get the following error :

Data error!

This error is caused by a corrupt mime type cache file. Rename the file and cPanel will generate a new one.

mv -v /home/<user>/.cpanel/datastore/SYSTEMMIME{,.bak}

How to read the summary area fields describing CPU statistics from the top command log ?

When you run the "top" command in SSH , you get the results as following :

top - 19:46:04 up 18 days, 4 min, 1 user, load average: 0.16, 0.24, 0.27

Tasks: 138 total, 1 running, 137 sleeping, 0 stopped, 0 zombie

Cpu(s): 5.1%us, 2.4%sy, 0.2%ni, 89.5%id, 2.7%wa, 0.0%hi, 0.0%si, 0.0%st

Mem: 3887124k total, 3420008k used, 467116k free, 419972k buffers

Swap: 8392696k total, 269884k used, 8122812k free, 1395624k cached

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND

1 **** 20 0 19356 1052 836 S 0.0 0.0 0:06.04 init

2 **** 20 0 0 0 0 S 0.0 0.0 0:00.00 kthreadd

3 **** RT 0 0 0 0 S 0.0 0.0 0:10.97 migration/0

4 **** 20 0 0 0 0 S 0.0 0.0 0:50.46 ksoftirqd/0

In this cpu(s) line can be read as following :

{ Cpu(s): 5.1%us, 2.4%sy, 0.2%ni, 89.5%id, 2.7%wa, 0.0%hi, 0.0%si, 0.0%st }

us = user mode

sy = system mode

ni = low priority user mode (nice)

id = idle task

wa = I/O waiting

hi = servicing IRQs

si = servicing soft IRQs

st = steal (time given to other DomU instances)

You do not have permission to create subdomains of the server's hostname

Getting the following error while creating the subdomain in the cPanel:

You do not have permission to create subdomains of the server's hostname

Solution:

• Login to the "WHM" >> Go to "Server Configuration" >> Then go to "Tweak Settings"
• Enable the Following option in the "Tweak Settings": 
     Allow users to park subdomains of the server’s hostname.

How to check the number of current MYSQL connections ?

Following are the different ways to check the MYSQL Connections to the database:

The below command will show the full stat about the mysql connections :

mysql> SHOW FULL PROCESSLIST\G

To get the number of connection attempts (successful or not) to the MySQL server :

mysql> show processlist;

Following command will show the number of open connections :

mysql> SHOW STATUS WHERE variable_name = 'Threads_connected';

To find current conection status you can use the following command :

#mysqladmin extended-status | grep -wi 'threads_connected\|threads_running' | awk '{ print $2,$4}' 

 

This will show you:

Threads_connected 12

Threads_running 1