Apache Log viewing

tail -f /var/log/httpd/error_log

Resolutions:

•  
  • [crit] (28)No space left on device: Failed to create mutex
    • ipcs -s | grep apache | perl -e 'while (<STDIN>) { @a=split(/\s+/); print `ipcrm sem $a[1]`}'; /etc/init.d/httpd restart;ipcs -ls;
    • ipcs|grep apache|awk '{print $2}'|xargs -I {} ipcrm -s {}; /etc/init.d/httpd restart;ipcs -ls;

to see semaphore settings:

ipcs -ls

All four semaphore parameters can be changed in the proc file system without reboot:

echo 250 32000 250 128 > /proc/sys/kernel/sem

Alternatively, you can use sysctl(8) to change it:

sysctl -w kernel.sem="250 32000 250 128"

To make the change permanent, add or change the following line in the file /etc/sysctl.conf. This file is used during the boot process.

echo "kernel.sem=250 32000 250 128" >> /etc/sysctl.conf

to change user as root:  

su root

or

su

this will keep you in the same directory that you are in currently

to log in as root in root

su root -l

su -

to change the password of the user that you are currently using:

passwd

List the contents of a Directory :

ls -l

Copy Files:

cp -fRv <filename> <destination path>

Reference:

ss64

to Create an Archive:

tar -czvf <filename> <path to content>

Check who belongs to which groups

nano /etc/group

Check Service running

chconfig --list

Create md5 Hash for string:

echo -n "sourceforconversion" | md5sum

Find a process by name:

ps aux | grep <processname>

Check processes Running:

top -c

Kill a process by name:

killall <processname>

PLESK reconfigure your domain:

/usr/local/psa/admin/sbin/websrvmng -u --vhost-name=<domain name>