How to reset mysql root password

Login to database with user root,
then select database mysql and update password field with no password.
$ mysql -u root -p
mysql> use mysql;
mysql> update user set password = '' where user = 'root';
or, you may delete the password only for localhost:
mysql> update user set password = '' where user = 'root' and host = 'localhost';

Send mail bash script

Sample Shell Script Here are two samples of shell script to send an email:

1.

#!/bin/bash
# script to send simple email
# email subject
SUBJECT="SET-EMAIL-SUBJECT"
# Email To ?
EMAIL="admin@test.com"
# Email text/message
EMAILMESSAGE="/tmp/body.txt"
echo "This is an email message test"> $EMAILMESSAGE
echo "This is email text" >>$EMAILMESSAGE
# send an email using /bin/mail
/bin/mail -s "$SUBJECT" "$EMAIL" < $EMAILMESSAGE


2.

#!/bin/sh
while true
do

subject="your-email-bsubject"
mailaddr="admin@example.com"
message=`you-email-body`
encsubject=`echo $subject`

cat << EEE | mail -s "$encsubject" $mailaddr
$encsubject
$message
EEE
exit 0
done

How to check mail queue in qmail?

# /var/qmail/bin/qmail-qstat 
# nice find /var/qmail/queue/mess/ -type f | xargs grep '^From: '  | awk '{print $2}' | sort | uniq -c | sort -n | tail
# nice -20 find /var/qmail/queue/mess/ -type f |xargs egrep '^From|^To' |sort -k1 |uniq |sort -k2 |uniq -c -f 1 |sort -n |tail

The watch Linux command line tool

This little utility executes a program repeatedly at a set interval and displays its output.


I've been using it with mysqladmin's processlist command like this:

# watch -n 1 /usr/bin/mysqladmin -uroot -pMYPASSWORD  processlist

I 've been using with mysqladmin's processlist command for the Plesk installed server like this:

# watch -n 1 /usr/bin/mysqladmin -uadmin -p`cat /etc/psa/.psa.shadow`  processlist

Note that this does put your password on display at the top of the command window whilst watch is running. If you don't want that, you could write a little bash script instead like this one:

#!/bin/sh

while :
do
sleep 1
clear
mysqladmin -uroot -pMYPASSWORD processlist 
done

Either way, we get a display of the MySQL process list every second in a Terminal window and it becomes very easy to see which processes are causing trouble.

Find heavy processes in Linux

▽ CPU Usage rate descending order

# ps auxw | sort -k3 -nr

▽ Memory Usage rate descending order

# ps auxw | sort -k4 -nr

▽Memory Usage rate descending order

# ps auxww | less | sort -k4 -n