#Useful Linux Commands

#Check a disk

yum install smartmontools
/usr/sbin/smartctl -i /dev/sda

/usr/sbin/smartctl -t short /dev/sda

/usr/sbin/smartctl -a /dev/sda

#Set FSCK at reboot

touch /forcefsck

echo AUTOFSCK_DEF_CHECK=yes>>/etc/sysconfig/autofsck

#Save a cron

crontab -l>$USER+$HOSTNAME.cron

#Load a cron

crontab $USER+$HOSTNAME.cron

#ClamAV ERROR: Malformed database

rm -fr /usr/share/clamav/daily.cvd

rm -fr /usr/share/clamav/main.cld

rm -fr /usr/share/clamav/mirrors.dat

/usr/local/cpanel/3rdparty/bin/freshclam

/scripts/restartsrv_clamd

#Setup ClamAV to update daily

echo #!/bin/sh>/etc/cron.daily/freshclam

echo /usr/local/cpanel/3rdparty/bin/freshclam --quiet>/etc/cron.daily/freshclam

chmod 755 /etc/cron.daily/freshclam

#Replace strings in files

sed -e ‘s/OLDUSERNAME/NEWUSERNAME/g’ /etc/users > /etc/users2

mv -f /etc/users2 /etc/users

#bash: vzctl: command not found

export PATH=$PATH:/usr/sbin:/sbin

#Read exim log

tail -f /var/log/exim_mainlog

#Read exim log

tail -f /var/log/exim_mainlog

#Read maillog (dovecot)

tail -f /var/log/maillog

#Edit the dovecot (pop3) config

nano -w /etc/dovecot/dovecot.conf

#Virus scan using clamav

for i in `awk '!/nobody/{print $2 | "sort | uniq" }' /etc/userdomains | sort | uniq`; do /usr/local/cpanel/3rdparty/bin/clamscan -i -r /home/$i 2>>/dev/null; done >> /root/infections

#How to monitor the server during high load

top

sar

#eg: sar -f /var/log/sa/sa`date +%d` | less

#Search for string in files, out filename, and line number

grep -H -r "string here" /home/user/

#Filter files

ls -allh | grep Oct | awk {'print $9'} | xargs file

#Mirror an MP3 site

wget -dc -np -H --mirror -UMSIE6 -Amp3 URL

#Archive files

tar -cf backup.tar file1.txt file2.txt file3.txt

tar -cfz backup.tar.gz dir

#Search messages log for named on a certain date

cat /var/log/messages | grep named | grep "Sep 26" | grep near

#Upgrading PHP on CentOS

#CentOS 4

cd

wget -q -O - http://www.atomicorp.com/installers/atomic.sh | sh

yum --en=atomic update php

#CentOS 5

cd /etc/yum.repos.d

wget http://dev.centos.org/centos/5/CentOS-Testing.repo

yum --en=c5-testing update php

#Setup NTP

yum -y install ntp

chkconfig ntpd on

ntpdate uk.pool.ntp.org

/etc/init.d/ntpd start

#Setup latest imagick

cvs -d :pserver:cvsread@cvs.php.net/repository checkout pecl/imagick && cd pecl/imagick && phpize && ./configure

#Find the distro

cat /etc/redhat-release

#Count lines in all php files in a dir

find . -name "*.php" | xargs wc -l

#Shows hard disk drives in Megs and Gigs

df -h

#Find out which users are taking up disk space use

du -sh /home/*

du /home | sort -rn

du -h /home | sort -rh

ncdu

#Find out which OpenVZ container is taking up disk space use

du -sh /vz/private/*

#Find ftp passwords

find '/home/' -type f -name '*' -size -10000k -exec grep -i -e 'ftp\:\/\/.*\:.*\@.*' {} \;

#Hardware Details

#Prerequisites

apt-get install dmidecode

#or

yum install dmidecode

#Usage: dmidecode | more

echo 'Type: ' `/usr/sbin/dmidecode --string system-product-name`

echo 'Serial: ' `/usr/sbin/dmidecode --string system-serial-number`

echo 'RAM: ' `grep '^MemTotal:' /proc/meminfo | awk '{ mem=($2)/(1024)/1024 ; printf "%0.0fGB\n", mem }'`

echo 'CPU: ' `grep -c ^processor /proc/cpuinfo`x `grep 'model name' /proc/cpuinfo | uniq | awk -F': ' '{print $2}'`

echo 'HDD: ' `df -h | awk 'BEGIN {tot=0} {tot=tot+$1} END {print (tot)}'GB`

#Finds .htaccess that have errordocument 401 in them

find /home/ -type f -name '.htaccess' -exec grep "ErrorDocument 401" {} \; -print

#Config the firewall from an interface

system-config-securitylevel

#Watch your messages constantly

tail -f /var/log/messages

#Set HOSTNAME

nano /etc/sysconfig/network

#Configure network

system-config-network

#Port forwarding for VNC

/sbin/iptables -A PREROUTING -t nat -p tcp -d $NATIP --dport 5900 -m state --state NEW,ESTABLISHED,RELATED -j DNAT --to 192.168.0.2:5900

#Port forwarding for HTTPD

/sbin/iptables -A PREROUTING -t nat -p tcp -d $NATIP --dport 81 -m state --state NEW,ESTABLISHED,RELATED -j DNAT --to 192.168.0.2:80

#Startup

#chkconfig [--level <levels>] <name> <on|off|reset>

#eg:

chkconfig --add pure-ftpd

chkconfig --level 345 pure-ftpd on

#or

ntsysv

#Change password via command line

#requires: apt-get install whois (for mkpasswd)

usermod -p `mkpasswd -H md5 password`

#alternative

echo df90jk42390kd | passwd backup --stdin

#Watch the httpd/monitor apache

cd /proc;watch " ls -al */cwd|grep public_html"

#Monitor apache httpd logs

tail -f /usr/local/apache/logs/error_log

tail -f /usr/local/apache/logs/access_log

tail -f /usr/local/apache/logs/*

#or

tail -f /var/log/httpd/error_log

tail -f /var/log/httpd/access_log

tail -f /var/log/httpd/*

#Show all processes

#This command will show all active processes in a tree view:

ps auxfc

#Top 10 memory using processes

ps -auxf | sort -nr -k 4 | head -10

#Using netstat

#How to list the connections to port 80

netstat -alntp | grep :80

#How to check the number of connections to port 80

netstat -alntp | grep :80 | wc -l

#How to list the remote IPs connecting to your server on port 80

netstat -alntp | grep :80 | awk '{print $5}' | cut -d: -f1 | sort

#How to list the uniq remote IPs and the number of connections from each IP

netstat -alntp | grep :80 | awk '{print $5}' | cut -d: -f1 | sort | uniq -c | sort -n

#MySQL Top

#Quick and dirty:

watch mysqladmin proc

#Full featured (if installed):

mytop

#Change shell

chsh <user> -s /bin/bash

#This will change the shell to bash for the <user>.

#Migrate MySQL database

mysqldump tom_wp > tom_wp.sql

mysql dave_wp < tom_wp.sql

#Find possible malicious code infections

grep -r "base64_decode" .

grep --include="*.php" -r "base64_decode" . | grep -v '.off' | grep -v 'virtfs' | more

grep --include="*.php" -r "String.fromCharCode" . | grep -v '.off' | grep -v 'virtfs' | more

#Force Reinstall MySQL daemon

service mysqld stop

rm -fr /var/lib/mysql

mv -f /etc/my.cnf /etc/my.cnf.old

rm /var/log/mysqld.log*

yum remove mysql-server

yum install mysql-server

service mysqld start

#Set the timezone

#Using system-config-date

yum install system-config-date

system-config-date

#Or, just files:

echo 'Europe/London' >/etc/timezone

ln -sf /usr/share/zoneinfo/Europe/London /etc/localtime

#Setup Xdebug

yum install php-devel gcc gcc-c++ autoconf automake

pecl install Xdebug

echo "; Enable xdebug extension module" > /etc/php.d/xdebug.ini

echo ";extension=xdebug.so" >> /etc/php.d/xdebug.ini

echo "zend_extension=/usr/lib/php/modules/xdebug.so" >> /etc/php.d/xdebug.ini

#Troubleshoot /bin/rm: Argument list too long

find . -name '*.phurix.com*' -print0 | xargs -0 rm

#cPanel virus scan using clamav

for i in `awk '!/nobody/{print $2 | "sort | uniq" }' /etc/userdomains | sort | uniq`; do /usr/local/cpanel/3rdparty/bin/clamscan -i -r /home/$i 2>>/dev/null; done >> /root/infections&

#Live tail of the cPanel error log

tail -f /usr/local/cpanel/logs/error_log

#Tail the httpd error log

tail -f /etc/httpd/logs/error_log

#Tail the httpd access log

tail -f /etc/httpd/logs/access_log

#Force restart the HTTPD

killall httpd; /scripts/restartsrv_httpd

#Restart MySQL service

/scripts/restartsrv_mysql

#Suspend/Unsuspend? a user account

/scripts/suspendacct <username>

/scripts/unsuspendacct <username>

#List of all the error_log files on the server

find /home -name error_log

#Find large files (over 1gb) on disk

find / -type f -size 1000000k

#Force a Backup to run on cPanel

/usr/local/cpanel/bin/backup --force

#EOF