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The watch Linux command line tool

I'm sure everyone else already knows about watch, but it's new to me. 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

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 from a friend of mine:


#!/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.

This entry was posted on Friday, 24th July 2009 at 07:42 and is filed under Software. You can follow any responses to this entry through the RSS 2.0 feed. You can skip to the end and leave a response. Pinging is currently not allowed.

7 Responses to “The watch Linux command line tool”

  1. 1 Henrik Olsen
    July 24th, 2009 at 10:41 #

    Watch is nice. But for this purpose you could also use mytop.

  2. 2 Dave Marshall
    July 24th, 2009 at 10:47 #

    Watch is cool, but mytop is a neat little replacement for what you're doing.

    http://jeremy.zawodny.com/mysql/mytop/

  3. 3 Rob...
    July 24th, 2009 at 11:00 #

    Thanks for the heads up on mytop :)

    Regards,

    Rob...

  4. 4 Rob T.
    July 26th, 2009 at 15:02 #

    While mytop and friends are better for this particular task, it is worth pointing out
    that mysql, mysqldump, etc. take an argument --defaults-file=filename. This allows you to put the user name & password in a file that won't show up in the process list.

    --Rob T.

  5. 5 Rob...
    July 27th, 2009 at 22:32 #

    Thanks Rob!

    Of course, one reason that I post about what I've learnt is so that people who know more than I do can chip in :)

    Regards,

    Rob...

  6. 6 LesTR
    July 28th, 2009 at 07:34 #

    Do while was not necessary.
    lestr@lestr-nb:~$ export MYUSER="root"
    lestr@lestr-nb:~$ echo $MYUSER
    root
    lestr@lestr-nb:~$ mysqladmin -u $MYUSER processlist
    +-----+------+-----------+----+---------+------+-------+------------------+
    | Id | User | Host | db | Command | Time | State | Info |
    +-----+------+-----------+----+---------+------+-------+------------------+
    | 218 | root | localhost | | Query | 0 | | show processlist |
    +-----+------+-----------+----+---------+------+-------+------------------+
    lestr@lestr-nb:~$

    But mtop is better : ))

  7. 7 Dave
    July 29th, 2009 at 06:48 #

    Hey Rob. Put your password in ~/.my.cnf :)

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