Posts Tagged ‘dev’
Wednesday, September 16th, 2009 I tried using festival today just to realize it doesn’t work anymore.
For instance # echo test |festival -tts would fail with the annoying
“Linux: can’t open /dev/dsp” error message. I found the solution in ubuntuforums,
the solution is originally taken from “the Gentoo Speechd Howto“.
The solution is to create .festivalrc in your home as well as to the homes of all usersintending to use festival.
Here is how:
printf ";use ALSAn(Parameter.set 'Audio_Method 'Audio_Command)n(Parameter.set 'Audio_Command "aplay -q -c 1 -t raw -f s16 -r $SR $FILE")n" > .festivalrc
Tags: alsa, dev, doesn, dsp, echo, fix, home, Linux, message, solution, today, use, work
Posted in Linux and FreeBSD Desktop, Linux Audio & Video | No Comments »
Wednesday, February 1st, 2012 Earlier I've blogged on How to Work Around periodically occuring TrackPoint Thinkpad R61 issues on GNU / Linux . Actually I thought the fix I suggested there is working but I was wrong as the problems with the trackpoint reappeared at twice or thrice a day.
My suggested fix was the use of one script that does periodically change the trackpoint speed and sensitivity to certain numbers.
The fix script to the trackpoint hanging issue is here
Originally I wrote the script has to be set to execute through crontab on a periods like:
0,30 * * * * /usr/sbin/restart_trackpoint.sh >/dev/null 2>&1
Actually the correct values for the crontab if you use my restart_trackpoint.sh script are:
0,5,10,15,20,25,30,35,40,45,50,55,58 * * * * /usr/sbin/restart_trackpoint.sh >/dev/null 2>&3
ig it has to be set the script is issued every 5 minutes to minimize the possibility for the Thinkpad trackpoint hang up issue.
One other thing that helps if trackpoint stucks is setting in /etc/rc.local is psmouse module to load with resetafter= parameter:
echo '/sbin/rmmod psmouse; /sbin/modprobe psmouse resetafter=30' >> /etc/rc.local
Tags: amp, blogged, change, correct values, crontab, dev, fix, gnu linux, hang ups, ig, issue, issue one, Linux, modprobe, Module, mouse, mouse pointer, nbsp, null, parameter, periods, psmouse, resetafter, rmmod, sbin, sensitivity, speed, stucks, thinkpad, thrice, trackpoint, ups, use, usr
Posted in Linux, Linux and FreeBSD Desktop, Linux Audio & Video | 1 Comment »
Thursday, December 8th, 2011 The usual way that one is supposed to check a certain partition let’s say /dev/sda1 disk UUID (Universal Unique Identifier) label is through a command:
vol_id /dev/sda1
For reason however Debian does not include vol_id command. To check the UUID assigned disk labels on Debian one should use another command called blkid (part of util-linux deb package).
blkid will list all block device attributes so it doesn’t specifically, passing any partition as argument.
Here is an example output of blkid :
server:/root# blkid
/dev/sda1: UUID="cdb1836e-b7a2-4cc7-b666-8d2aa31b2da4" SEC_TYPE="ext2" TYPE="ext3"
/dev/sda5: UUID="c67d6d43-a48f-43ff-9d65-7c707a57dfe6" TYPE="swap"
/dev/sdb1: UUID="e324ec28-cf04-4e2e-8953-b6a8e6482425" TYPE="ext2"
/dev/sdb5: UUID="1DWe0F-Of9d-Sl1J-8pXW-PLpy-Wf9s-SsyZfQ" TYPE="LVM2_member"
/dev/mapper/computer-root: UUID="fbdfc19e-6ec8-4000-af8a-cde62926e395" TYPE="ext3"
/dev/mapper/computer-swap_1: UUID="e69100ab-9ef4-45df-a6aa-886a981e5f26" TYPE="swap"
/dev/mapper/computer-home: UUID="2fe446da-242d-4cca-8b2c-d23c76fa27ec" TYPE="ext3"
Tags: cca, command, computer swap, deb, deb package, debian gnu, dev, Disk, disk labels, doesn, DWe, ext, ff, gnu linux, Linux, linux deb, LVM, mapper, package, partition, partition disk, quot dev, reason, root, sda, sdb, sec type, server root, Unique, UUID, vol, way
Posted in Linux, System Administration, Various | No Comments »
Thursday, October 27th, 2011 I just installed munin to track in web the performance of few Debian servers. I’ve configured munin to open via a Virtualhosts in Apache. As its always wise to protect any statistics data about the server from the unwanted possible security violators, I decided to protect Munin with Apache .htaccess.
The munin htmldir output dir is configured to be in /var/www/munin, hence I protected my munin with password by:
1. Creating .htaccess file in /var/www/munin with following content
AuthUserFile /etc/apache2/.munin_htpasswd
AuthGroupFile /dev/null
AuthName EnterPassword
AuthType Basic
require user admin
2. Creating /etc/apache2/.munin_htpasswd with htpasswd (htaccess password generator cmd)
debian:/var/www/munin# htpasswd -c /etc/apache2/.munin_htpasswd admin
New password:
Re-type new password:
Adding password for user admin
Another important thing I had to do is set my VirtualHost file to be configured with AllowOverride All , if AllowOverride All is missing the .htaccess and .htpasswd are not red at all.
Afterwards munin is protected with password, and when my virtualdomain where munin lays e.g. http://munin.mydomain.com is accessed the .htpasswd password dialog pops up 😉
Tags: Allowoverride, apache, apache htaccess, AuthGroupFile, AuthType, AuthUserFile, Creating, data, dev, dialog, dir, EnterPassword, generator, GNU, htaccess password generator, htpasswd, Linux, null, password, performance, pops, security, servers, statistics data, var, Virtualhost, web statistics, www
Posted in Linux, System Administration, Web and CMS | No Comments »
Saturday, July 16th, 2011 
It was necessery to clean up some squid cache for some proxy users on a Debian host. Until now I’ve used to run only custom build Squid server on Slackware Linux.
Thus I was curious if Debian guys were smart enough to implement a proxy cache cleaning option as an option to be passed on to squid’s init script.
Honestly I was quite suprised squid clear cache option is not there;
squid-cache:~# /etc/init.d/squid3
Usage: /etc/init.d/squid3 {start|stop|reload|force-reload|restart}
squid-cache:/#
As it was not embedded into init script I still hoped, there might be some Debian way to do the proxy cache clearing, so I spend some 10 minutes checking online as well as checked in squid3‘s manual just to find there is no specific command or Debian accepted way to clean squid’s cache.
Since I couldn’t find any Debian specific, way I did it the old fashioned way 😉 (deleted directory/file structures in /var/spool/squid3/* and used squid’s -z option, to recreate the swap directories.
Here is how:
squid-cache:~# /etc/init.d/squid3 stop;
squid-cache:~# rm -Rf /var/spool/squid3/*;
squid-cache:~# squid3 -z; /etc/init.d/squid3 start
Finally I was quite amazed to realize, there was not even a crontab script to periodically clear and re-create proxy cache.
My previous experience with maintaning an office Squid proxy cache has prooved, that periodic cache clean ups are very helpful, especially to resolve issues with cached unreslovable DNS entries in the server.
Clearing up squid cache every week or something, guarantees that failure to resolve certain hosts at certain times would not stay unresolvable like forever 😉
In that manner of thougths, I decided to put the following crontab which will twice a month clear up proxy’s cache, to possibly solve some failed squid DNS issues.
squid-cache:~# crontab -u root -l > file;
echo '00 04 12,26 * * /etc/init.d/squid3 stop; rm -Rf /var/spool/squid3/*; squid3 -z; /etc/init.d/squid3 start >/dev/null 2>&1'
>> file; crontab file
By the way, implementing the squid clear cache in Debian and Ubuntu ‘s init scripts and putting a periodic proxy clear up cron, seems like a feature worthy to be proposed to the distro developers and hopefully be embbed in some of the upcoming distro releases 😉
Tags: amp, cache option, clear cache, clearing, command, cron, crontab script, dev, DNS, dns entries, experience, failure, feature, fi, fil, file, file structures, guarantees, Honestly, hosts, init script, Linux, necessery, online, option, proxy, proxy cache, proxy users, rf, root, something, specific, spool, squid, squid cache, Stop, thougths, Ubuntu, ups, Usage, var, way
Posted in Linux, System Administration | No Comments »
Wednesday, July 13th, 2011 One server with a broken Raid array was having troubles with it’s software raid.
I tried to scan the raid array via a rescue cd like so:
server:~# mdadm --assemble --scan /dev/md1
just to be suprised by the message:
mdadm: /dev/md1 assembled from 2 drives – not enough to start the array.
In /proc/mdstat respectively the raid was showing inactive, e.g.:
server:~# cat /proc/mdstat
Personalities : [raid10] [raid1]
md1 : inactive sda2[0] sdc2[2] sdb2[1]
12024384 blocks
Respectively trying to activate the software Linux raid array with:
server:~# mdadm -A -s
Couldn’t be completed because of the same annoying error:
/dev/md1 assembled from 2 drives – not enough to start the array.
Thanksfully finally thanks to some Russian, who posted having same issues reported to be able to active his software RAID with mdadm’s –force option.
Thus enabling the problematic RAID 5 array was possible with:
server:~# mdadm -A -s --force
This solution of course is temporary and will have to further check what’s wrong with the array, however at least now I can chroot to the server’s / directory. 😉
Tags: annoying error, cat, check, course, dev, drive, ERROR, force option, Linux, md1, mdstat, option, Personalities, proc, Raid, raid 5 array, raid array, rescue, rescue cd, sCould, sda, sdb, sdc, software, software linux, software raid, solution, Thanksfully, way
Posted in Linux, System Administration | 1 Comment »
Saturday, July 9th, 2011 I’m currently writting a script which is supposed to be adding new crontab jobs and do a bunch of other mambo jambo.
By so far I’ve been aware of only one way to add a cronjob non-interactively like so:
linux:~# echo '*/5 * * * * /root/myscript.sh' | crontab -
Though using the | crontab – would work it has one major pitfall, I did completely forgot | crontab – OVERWRITES CURRENT CRONTAB! with the crontab passed by with the echo command.
One must be extremely careful if he decides to use the above example as you might loose your crontab definitions permanently!
Thanksfully it seems there is another way to add crontabs non interactively via a script, as I couldn’t find any good blog which explained something different from the classical example with pipe to crontab –, I dropped by in the good old irc.freenode.net to consult the bash gurus there 😉
So I entered irc and asked the question how can I add a crontab via bash shell script without overwritting my old existing crontab definitions less than a minute later one guy with a nickname geirha was kind enough to explain me how to get around the annoying overwridding.
The solution to the ovewrite was expected, first you use crontab to dump current crontab lines to a file and then you append the new cron job as a new record in the file and finally you ask the crontab program to read and insert the crontab definitions from the newly created files.
So here is the exact code one could run inside a script to include new crontab jobs, next to the already present ones:
linux:~# crontab -l > file; echo '*/5 * * * * /root/myscript.sh >/dev/null 2>&1' >> file; crontab file
The above definition as you could read would make the new record of */5 * * * * /root/myscript.sh >/dev/null be added next to the existing crontab scheduled jobs.
Now I’ll continue with my scripting, in the mean time I hope this will be of use to someone out there 😉
Tags: bash scripts, bash shell script, blog, classical example, cron, cron job, cron jobs, crontab, definitions, dev, echo, echo 5, echo command, exact code, file, fileThe, gurus, irc, jambo, kind, line, Linux, mambo jambo, mean time, minute, nbsp nbsp nbsp nbsp nbsp, nickname, ovewrite, pipe, pitfall, root, scripting, Shell, solution, someone, Thanksfully, time, use, way
Posted in Linux, System Administration | 9 Comments »
Wednesday, April 20th, 2011 I’m using a backtrack Linux to recover a broken Ubuntu Linux, to fix this disastrous situation I’m using the Ubuntu Linux through chroot after mounting my /dev/sda1, where my Linux resides with:
linux-recovery:~# mkdir /mnt/test1
linux-recovery:~# mount /dev/sda1 /mnt/test1
linux-recovery:~# chroot /mnt/test1
ubuntu:~#
I consequently needed to mount up the /proc and /dev partition inside the chroot environment.
Here is how I did it:
ubuntu:~# mount /proc
ubuntu:~# mount -a
Next I switched on on a different virtual console in the backtrack and to mount /dev issued the commands:
linux-recovery:~# mount --bind /dev /mnt/test1/dev
Now once again, I can use theapt-get inside the chroot to fix up the whole mess …
Tags: aNext, backtrack, backtrack linux, Bind, chroot, chroot environment, dev, devNow, disastrous situation, environment, Linux, mess, mkdir, mnt, mount dev, partition, proc, procubuntu, sda, situation, test, test1, Ubuntu, ubuntu linux
Posted in Linux | 2 Comments »
