Posts Tagged ‘iname’

How to disable tidy HTML corrector and validator to output error and warning messages

Sunday, March 18th, 2012

Reading Time: 2minutes

I've noticed in /var/log/apache2/error.log on one of the Debian servers I manage a lot of warnings and errors produced by tidy HTML syntax checker and reformatter program.

There were actually quite plenty frequently appearing messages in the the log like:

...
To learn more about HTML Tidy see http://tidy.sourceforge.net
Please fill bug reports and queries using the "tracker" on the Tidy web site.
Additionally, questions can be sent to html-tidy@w3.org
HTML and CSS specifications are available from http://www.w3.org/
Lobby your company to join W3C, see http://www.w3.org/Consortium
line 1 column 1 - Warning: missing <!DOCTYPE> declaration
line 1 column 1 - Warning: plain text isn't allowed in <head> elements
line 1 column 1 - Info: <head> previously mentioned
line 1 column 1 - Warning: inserting implicit <body>
line 1 column 1 - Warning: inserting missing 'title' element
Info: Document content looks like HTML 3.2
4 warnings, 0 errors were found!
...

I did a quick investigation on where from this messages are logged in error.log, and discovered few .php scripts in one of the websites containing the tidy string.
I used Linux find + grep cmds find in all php files the "tidy "string, like so:

server:~# find . -iname '*.php'-exec grep -rli 'tidy' '{}' ;
find . -iname '*.php' -exec grep -rli 'tidy' '{}' ; ./new_design/modules/index.mod.php
./modules/index.mod.php
./modules/index_1.mod.php
./modules/index1.mod.php

Opening the files, with vim to check about how tidy is invoked, revealed tidy calls like:

exec('/usr/bin/tidy -e -ashtml -utf8 '.$tmp_name,$rett);

As you see the PHP programmers who wrote this website, made a bigtidy mess. Instead of using php5's tidy module, they hard coded tidy external command to be invoked via php's exec(); external tidy command invocation.
This is extremely bad practice, since it spawns the command via a pseudo limited apache shell.
I've notified about the issue, but I don't know when, the external tidy calls will be rewritten.

Until the external tidy invocations are rewritten to use the php tidy module, I decided to at least remove the tidy warnings and errors output.

To remove the warning and error messages I've changed:

exec('/usr/bin/tidy -e -ashtml -utf8 '.$tmp_name,$rett);

exec('/usr/bin/tidy --show-warnings no --show-errors no -q -e -ashtml -utf8 '.$tmp_name,$rett);

The extra switches meaning is like so:

q – instructs tidy to produce quiet output
-e – show only errors and warnings
–show warnings no && –show errors no, completely disable warnings and error output

Onwards tidy no longer logs junk messages in error.log Not logging all this useless warnings and errors has positive effect on overall server performance especially, when the scripts, running /usr/bin/tidy are called as frequently as 1000 times per sec. or more

Find all hidden files in Linux, Delete, Copy, Move all hidden files

Tuesday, April 15th, 2014

Reading Time: 2minutes

search-find-all-hidden-files-linux-delete-all-hidden-files
Listing hidden files is one of the common thing to do as sys admin. Doing manipulations with hidden files like copy / delete / move is very rare but still sometimes necessary here is how to do all this.

1. Find and show (only) all hidden files in current directory

find . -iname '.*' -maxdepth 1

maxdepth – makes files show only in 1 directory depth (only in current directory), for instance to list files in 2 subdirectories use -maxdepth 3 etc.

echo .*;

Yeah if you're Linux newbie it is useful to know echo command can be used instead of ls.
echo * command is very useful on systems with missing ls (for example if you mistakenly deleted it 🙂 )

2. Find and show (only) all hidden directories, sub-directories in current directory

To list all directories use cmd:

find /path/to/destination/ -iname ".*" -maxdepth 1 -type d

3. Log found hidden files / directories

find . -iname ".*" -maxdept 1 -type f | tee -a hidden_files.log

find . -iname ".*" -maxdepth 1 type d | tee -a hidden_directories.log
4. Delete all hidden files in current directory

cd /somedirectory
find . -iname ".*" -maxdepth 1 -type f -delete

5. Delete all hidden files in current directory

cd /somedirectory
find . -iname ".*" -maxdepth 1 -type d -delete

6. Copy all hidden files from current directory to other "backup" dir

find . -iname ".*" -maxdepth 1 -type f -exec cp -rpf '{}' directory-to-copy-to/ ;

7. Copy and move all hidden sub-directories from current directory to other "backup" dir

find . -iname ".*" -maxdepth 1 -type d -exec cp -rpf '{}' directory-to-copy-to/ ;

– Moving all hidden sub-directories from current directory to backup dir

find . -iname ".*" -maxdepth 1 -type d -exec mv '{}' directory-to-copy-to/ ;

 

How to count how many files are in a directory with find on Linux

Tuesday, February 21st, 2012

Reading Time: 3minutes

how to count how many directories are on your linux server

Did you ever needed to count, how many files in a directory are there?
Having the concrete number of files in a directory is not a seldom task but still very useful especially for scripts or simply for the sake of learning

The quickest and maybe the easiest way to count all files in a directory in Linux is with a combination of find and wc commands:

Here is how;

linux:~# cd ascii
linux:~/ascii# find . -type f -iname '*' -print |wc -l
407

This will find and list all matched files in any directory and subdirectories, print them out and count them with wc command.
The -type f argument instructs find to look only for files.

Other helpful variance of finding and listing all files in a directory and subdirectories is to list and count all the files with a certain file extension under a directory. For example, lets list all text files (.txt) contained in a directory and all level sub-directories:

linux:~/ascii# find . -type f -iname '*.txt' -print |wc -l
401

If you need to check the number of files in a directory for multiple directories on a server and you're aiming at doing it efficienly, issung above find .. | wc code will definitely be not a good choice. If used it will generate heavy load for the system and along with that will complete the execution in ages if issued on a large number of files containing dirs.

Thanksfully if efficiency is targetted, there is a command written in C called tree which is more efficient than find.
To count the number of files in dir but using tree :

linux:~# cd ascii
linux:/ascii# tree | tail -n 1
32 directories, 407 files

By default tree prints info for both the number of found files and directories.
To print out only the files matched, awk comes handy, e.g.:

linux:/ascii# tree |tail -n 1| awk '{ print $3 }'407

To list only the number of files in a directory without its existing sub-directories ls + wc use is also possible:

linux:~/ascii# ls -l | grep ^- | wc -l68

This result the above command would produce is +1 more than the real number of files, as it counts the directory ".." as one file (in UNIX / LINUX everything is file).

A short one liner script that can calculate all files correctly by substracting 1 is and hence present correct result on number of files is like so:

linux:~/ascii# var=$(ls -l | grep ^- | wc -l); var=$(($var - 1)); echo $var

ls can be used to calculate the number of 1-st level sub-directories under certain directory for instance:

linux:~/ascii# ls -l |grep ^d|wc -l
25

You see the ascii directory has 25 subdirectories in its 1st level.

To check symlinks under a directory with ls the command would be:

linux:~/ascii# ls -l | grep ^l | wc -l
0

Note above 3 ls | grep … examples, will not work properly if the directory contains files with SUID or some special properties set.
Hence to get the same 3 results for active files, directories and symbolic links, a one liner similar to the one below can be used instead:

linux:~/ascii# for t in files links directories; do echo `find . -type ${t:0:1} | wc -l` $t; done 2> /dev/null
407 files
0 links
33 directories

This will show statistics about all files, links and directories for all directory sub-levels.
Just in case if there is need to only count files, links and directories without directory recursion enabled, use:

linux:~/ascii# for t in files links directories; do echo `find . -maxdepth 1 -type ${t:0:1} | wc -l` $t; done 2> /dev/null
68 files
0 links
26 directories

Anyways the above bash loop will be slow, for directories containing thousands of files. For better performance the equivallent of above bash loop rewritten in perl would be:

linux:~/ascii# ls -l |perl -e 'while(<>){$h{substr($_,0,1)}+=1;} END {foreach(keys %h) {print "$_ $h{$_}\n";}}'
- 68
d 25
t 1
linux:~/ascii#
In any case the most preferrable and efficient way to count files en directories is by using tree command.
In my view using always tree command instead of code "hacks" is smart idea.

In Slackware tree command is part of the base install, on Debian and CentOS Linux, tree cmd is not part of the base system and requires install via apt / yum e.g.:

debian:~# apt-get --yes install tree
...

[root@centos:~ ]# yum --yes install tree

Happy counting 😉

How to disable ACPI (power saving) support in FreeBSD / Disable acpi on BSD kernel boot time

Tuesday, May 15th, 2012

Reading Time: 3minutes

FreeBSD disable ACPI how ACPI Basic works basic diagram

On FreeBSD the default kernel is compiled to support ACPI. Most of the modern PCs has already embedded support for ACPI power saving instructions.
Therefore a default installed FreeBSD is trying to take advantage of this at cases and is trying to save energy.
This is not too useful on servers, because saving energy could have at times a bad impact on server performance if the server is heavy loaded at times and not so loaded at other times of the day.

Besides that on servers saving energy shouldn't be the main motivator but server stability and productivity is. Therefore in my personal view on FreeBSD used on servers it is better to disable complete the ACPI in order to disable CPU fan control to change rotation speeds all the time from low to high rotation cycles and vice versa at times of low / high server load.

Another benefit of removing the ACPI support on a server is this would probably increase the CPU fan life span and possibly prevent the CPU to be severely heated at times.

Moreover, some piece of hardware might have troubles in properly supporting ACPI specifications and thus ACPI could be a reason for unexpected machine hang ups.

With all said I would recommend to anyone willing to use BSD for a server to disable the ACPI (Advanced Configuration and Power Interface), just like I did.

Here is how;

1. Quick review on how ACPI is handled on FreeBSD

acpi support is being handled on FreeBSD by a number of loadable kernel modules, here is a complete list of all the kernel modules dealins with acpi:

freebsd# cd /boot
freebsd# find . -iname '*acpi*.ko'
./kernel/acpi.ko
./kernel/acpi_aiboost.ko
./kernel/acpi_asus.ko
./kernel/acpi_fujitsu.ko
./kernel/acpi_ibm.ko
./kernel/acpi_panasonic.ko
./kernel/acpi_sony.ko
./kernel/acpi_toshiba.ko
./kernel/acpi_video.ko
./kernel/acpi_dock.ko

By default on FreeBSD, if hardware has some support for ACPI the acpi gets activated by acpi.ko kernel module. The specific type of vendors specific ACPI like IBM, ASUS, Fujitsu are controlled by the respective kernel module from the list …

Hence, to control if ACPI is loaded or not on a FreeBSD system with no need to reboot one can use kldload, kldunload module management BSD cmds.

a) Check if acpi is loaded on a BSD

freebsd# kldstatkldstat | grep -i acpi
9 1 0xc9260000 57000 acpi.ko

b) unload kernel enabled ACPI support

freebsd# kldunload acpi

c) Load acpi support (not the case with me but someone might need it, if for instance BSD is running on laptop)

freebsd# kldload acpi

2. Disabling ACPI to load on bootup on BSD

a) In /boot/loader.conf add the following variables:

hint.acpi.0.disabled="1"
hint.p4tcc.0.disabled=1
hint.acpi_throttle.0.disabled=1


b) in /boot/device.hints add:

hint.acpi.0.disabled="1"

c) in /boot/defaults/loader.conf make sure:

##############################################################
### ACPI settings ##########################################
##############################################################
acpi_dsdt_load="NO" # DSDT Overriding
acpi_dsdt_type="acpi_dsdt" # Don't change this
acpi_dsdt_name="/boot/acpi_dsdt.aml"
# Override DSDT in BIOS by this file
acpi_video_load="NO" # Load the ACPI video extension driver

d) disable ACPI thermal monitoring

It is generally a good idea to disable the ACPI thermal monitoring, as many machines hardware does not support it.

To do so in /boot/loader.conf add

debug.acpi.disabled="thermal"

If you want to learn more on on how ACPI is being handled on BDSs check out:

freebsd# man acpi

Other alternative method to permanently wipe out ACPI support is by not compiling ACPI support in the kernel.
If that's the case in /usr/obj/usr/src/sys/GENERIC make sure device acpi is commented, e.g.:

##device acpi

 

How to disable or remove completely Adobe (Macromedia) Flash Cookies on Linux

Monday, April 11th, 2011

Reading Time: 2minutes
As I’ve mentioned in my previous post, one of the greatest “evils” which prevents a good internet anonymization whether you surf online is Adobe Flash Player

There are two approaches you might partake to disable the privacy issues which might be related to Adobe Flash cookies saving data about flash banners or websites which stores their cookies to your computer.

To find out if flash websites has already saved their nasty flash cookies on your Linux, issue the commands:

hipo@debian:~$ cd .macromedia
hipo@debian:/home/hipo/.macromedia$ find -iname '*.sol'
./Flash_Player/macromedia.com/support/flashplayer/sys/#s.ytimg.com/settings.sol
./Flash_Player/macromedia.com/support/flashplayer/sys/settings.sol
./Flash_Player/macromedia.com/support/flashplayer/sys/#ip-check.info/settings.sol

The returned output of the above find command clearly reveals the shitty flash has stored already 3 flash cookies on my Linux, 3 cookies which later can be easily requested by other flash banners.
The 3 flash cookies are:
1. Saved by Adobe’s Flash Configuration Manager
2. Saved by the website ip-check.info
3. Saved by s.ytimg.com’s website

Now to deal with the situation and get rid of flash cookies, there are possibly two ways of approach that one can take:

1. One is to use some kind of script like the one clear_flash_cookies.tsch the other one is to completely disable flash cookies.
Using the clear_flash_cookies.tcsh does get rid of flash cookie problems just temporary as it might be set to be executed either once the browser is starting up, or directly via some kind of cron job entry like:

01 11,19 * * * /home/hipo/scripts/clear_flash_cookies.tcsh

eHowever clearing up (removing) the flash cookies, still doesn’t completely proihibit saving up of flash cookies and in the time intervals between the clear ups of the flash cookies, still some websites might save information related to their use on your Linux host and expose this information for other external flash websites to read and retrieve information about your previous websites visits.

Therefore it might be a better solution in terms of browser security to;

2. completely disable the use of adobe flash cookies on your Linux powered desktop.

Disabling adobe flash cookies is possible by either using the online flash Global Storage Settings (Flash Settings Manager) by navigating to the URL:

http://www.macromedia.com/support/documentation/
en/flashplayer/help/settings_manager03.html

Adobe Flash Player online settings manager unticked option

And by removing the tick which is present to the option:

Allow third party Flash content to store data on your computer

Or by linking the local directory ~/.macromedia -> /dev/null

hipo@debian:~$ mv .macromedia .macromedia-bak
hipo@debian:~$ ln -s /dev/null .macromedia
hipo@debian:~$ ls -ald .macromedia
lrwxrwxrwx 1 hipo hipo 9 2009-03-30 09:56 .macromedia -> /dev/null

That’s all, Farewell nasty Flash cookies!