Posts Tagged ‘exec’
Wednesday, January 9th, 2013
Some time ago I've written a tiny article, explaining how converting of HTML or TEXT file content inside file can be converted with iconv.
Just recently, I've made mirror of a whole website with its directory structure with wget cmd. The website to be mirrored was encoded with charset Windows-1251 (which is now a bit obsolete and not very recommended to use), where my Apache Webserver to which I mirrored is configured by default to deliver file content (.html, txt, js, css …) in newer and more standard (universal cyrillic) compliant UTF-8 encoding. Thus opening in browser from my website, the website was delivered in UTF-8, whether the file content itself was with encoding Windows CP-1251; Thus I ended up seeing a lot of monkey unreadable characters instead of Slavonic letters. To deal with the inconvenience, I've used one liner script that converts all Windows-1251 charset files to UTF-8. This triggered me writting this little post, hoping the info might be useful to others in a similar situation to mine:
1. Make Mass file charset / encoding convertion with recode
On most Linux hosts, recode is probably not installed. If you're on Debian / Ubuntu Linux install it with apt;
apt-get install --yes recode
It is also installable from default repositories on Fedora, RHEL, CentOS with:
yum -y install recode
Here is recode description taken from man page:
NAME
recode – converts files between character sets
find . -name "*.html" -exec recode WINDOWS-1251..UTF-8 {} \;
If you have few file extensions whose chracter encoding needs to be converted lets say .html, .htm and .php use cmd:
find . -name "*.html" -o -name '*.htm' -o -name '*.php' -exec recode WINDOWS-1251..UTF-8 {} \;
Btw I just recently learned how one can look for few, file extensions with find under one liner the argument to pass is -o -name '*.file-extension', as you can see from example, you can look for as many different file extensions as you like with one find search command.
After completing the convertion, I've remembered that earlier I've also used iconv on a couple of occasions to convert from Cyrillic CP-1251 to Cyrillic UTF-8, thus for those who prefer to complete convertion with iconv here is an alternative a bit longer method using for cycle + mv and iconv.
2. Mass file convertion with iconv
for i in $(find . -name "*.html" -print); do
iconv -f WINDOWS-1251 -t UTF-8 $i > $i.utf-8;
mv $i $i.bak;
mv $i.utf-8 $i;
done
As you see in above line of code, there are two occurances of move command as one is backupping all .html files and second mv overwrites with files with converted encoding. For any other files different from .html, just change in cmd find . -iname '*.html' to whatever file extension.
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Tags: CentOS, character sets, convertion, converts, exec, file extensions, inconvenience, linux hosts, man page, page 3a, repositories, rhel, tiny article, unicode utf 8
Posted in Everyday Life, Linux, System Administration, Web and CMS | 1 Comment »
Wednesday, July 18th, 2012
At security critical hosts running Apache + PHP based sites it is recommended functions like:
system();
exec();shell_exec();.....
to be disabled. The reason is to mainly harden against script kiddies who might exploit your site/s and upload some shitty SK tool like PHP WebShell, PHP Shell and the probably thousands of “hacker” variations that exist nowdays.
In latest Debian stable Squeeze, suhosin – advanced protection module for php5 is being installed and enabled in Apache (by default).
Simply disabling a number of functions using suhosin, could prevent multiple of future headaches and hours of pondering on who 0wn3d your server ….
Disabling the basic PHP system(); and other similar functions which allows shell spawn is not always possible, since some websites or CMS platforms depends on them for proper runnig, anyways whether it is possible disabling ‘em is a must.
There are two ways to disable system(); functions; One is through using /etc/php5/apache2/conf.d/suhosin.ini and 2nd by adding a list of functions that has to be disabled directly in Website Virtualhost file or in apache2.conf (/etc/apache2/apache2.conf;
For people hosting multiple virtualhost websites on the same server using the custom domain Virtualhost method is probably better, since on a global scale the functions could be enabled if some of the websites hosted on the server requires exec(); to work OK. In any case using /etc/php5/apache2/conf.d/suhosin.ini to disable system(); functions in PHP is less messy …
1. Disabling PHP system(); fuctions through /etc/apache2/apache2.conf and custom site Vhosts
Place somewhere (I prefer near the end of config);;;
php_admin_flag safe_mode on
php_admin_value disable_functions "system, exec, shell_exec, passthru , ini_alter, dl, pfsockopen, openlog, syslog, readlink, symlink, link, leak, fsockopen, popen, escapeshellcmd, apache_child_terminate apache_get_modules, apache_get_version, apache_getenv, apache_note,apache_setenv,virtual"
Disabling it for custom virtualhost is done by simply adding above Apache directvies (before the closing tag in /etc/apache2/sites-enabled/custom-vhost.com
2. Disabling PHP system();, exec(); shell spawn with suhosin.ini
In /etc/php5/apache2/conf.d/suhosin.ini add;;
suhosin.executor.func.blacklist =system, exec, shell_exec, passthru, ini_alter, dl,
pfsockopen, openlog, syslog, readlink, symlink, link, leak, fsockopen, popen,
escapeshellcmd, apache_child_terminate apache_get_modules, apache_get_version,
apache_getenv, apache_note,apache_setenv,virtual
To do it directly via shell issue;;;
server: conf.d/# cd /etc/php5/apache2/conf.d/
server: conf.d# echo 'suhosin.executor.func.blacklist =system, exec, shell_exec, passthru, ini_alter, dl,' >> suhosin.ini
server: conf.d# echo 'pfsockopen, openlog, syslog, readlink, symlink, link, leak, fsockopen, popen,' >> suhosin.ini
server: conf.d# echo escapeshellcmd, apache_child_terminate apache_get_modules, apache_get_version,' >> suhosin.ini
server: conf.d# echo 'apache_getenv, apache_note,apache_setenv,virtual' >> suhosin.ini
Then to re-load the memory loaded Apache libphp library an Apache restart is necessary;
server: conf.d# /etc/init.d/apache2 restart
Restarting web server: apache2 ... waiting .
server: conf.d#
Tadam, this should be quite a good security against annoying automated script attacks. Cheers 
Tags: apache security, apache2, Auto, custom, custom domain, debian gnu, Draft, escapeshellcmd, exec, func, global scale, GNU, gnu linux, harden, headaches, ini, Linux, number, passthru, php admin, php5, popen, protection, reason, runnig, safe mode, script, script kiddies, Shell, squeeze, suhosin, symlink, syslog, system, system functions, tool, two ways, VhostsPlace, Virtualhost, WebShell
Posted in Computer Security, System Administration, Web and CMS | 2 Comments »
Monday, June 11th, 2012
After writting in previous article on how talk be used to handle interactive chat console sessions on FreeBSD, I thought of dropping a few lines on how same is done on Debian, so here is how:
1.; Install talk and talkd
noah:/home/hipo# apt-get --yes install talk talkd
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following NEW packages will be installed:
talk talkd
0 upgraded, 2 newly installed, 0 to remove and 93 not upgraded.
Need to get 19.0 kB/42.3 kB of archives.
After this operation, 201 kB of additional disk space will be used.
Get:1 http://ftp.nl.debian.org/debian/ stable/main talkd amd64 0.17-14 [19.0 kB]
Fetched 19.0 kB in 0s (67.1 kB/s)
Selecting previously deselected package talk.
(Reading database ... 90%
Unpacking talk (from .../talk_0.17-14_amd64.deb) ...
Selecting previously deselected package talkd.
Unpacking talkd (from .../talkd_0.17-14_amd64.deb) ...
Processing triggers for man-db ...
Setting up talk (0.17-14) ...
update-alternatives: using /usr/bin/netkit-ntalk to provide /usr/bin/talk (talk) in auto mode.
Setting up talkd (0.17-14) ...
2.;; Check and make sure talk and ntalkd lines are present in /etc/inetd.conf
noah:/home/hipo# grep -i talk /etc/inetd.conf
#:BSD: Shell, login, exec and talk are BSD protocols.
talk dgram udp wait nobody.tty /usr/sbin/in.talkd in.talkd
ntalk dgram udp wait nobody.tty /usr/sbin/in.ntalkd in.ntalkd
Now you probably wonder why are there two lines in /etc/inetd.conf for ))
in.talkd and in.ntald
in.talkd daemon's aim is to deliver talk sessions between logged in users on one Linux host with few logged in users willing to talk to each other locally;;
Wheter in.ntalkd is designed to serve interactive user talks between the host where in.ntalkd is installed and remote systems ruwhich have the talk client program installed. Of course in order for remote talks to work properly the firewall (if such has to be modified to allow in.ntalkd chats. I've never used in.ntalkd and on most machines having in.ntald hanging around from inetd, could be a potential security hole so, for people not planning to initiate remote TALKs between Unix / Linux / BSD hosts on a network it is a good practice the ntalkd line seen above in inetd.conf to be commented out ::;
noah:/home/hipo# grep -i talk /etc/inetd.conf
#:BSD: Shell, login, exec and talk are BSD protocols.
talk dgram udp wait nobody.tty /usr/sbin/in.talkd in.talkd
#ntalk dgram udp wait nobody.tty /usr/sbin/in.ntalkd in.ntalkd
3.;;; Restart openbsd-inetd init script and talk is ready to use
noah:~# /etc/init.d/openbsd-inetd restart
* Restarting internet superserver inetd
Onwards to use talk between two users the syntax is same like on other BSD, as a matter of fact TALK – console / terminal interactive chat originally was developed for the 4.2BSD UNIX release ;; the Linux code is a port of this BSD talk and not rewrite from scratch.
Using talk between two logged in users on pts/1 (lets say user test) and tty1 (user logged as root) is done with:
noah:~$ tty
noah:~$ talk root@localhost tty1
/dev/pts/1
On tty1 the user has to have enabled Talk sessions request, by default this behaviour in Debian and probably other Debian based Linuxes (Ubuntu) for instance is configured to have talks disabled, i,e ,,,
root@noah:~# mesg
is n
Enabling it on root console is done with:
root@noah:~# mesg y
Once enabled the root will be able to see the TALK service requests on tty1 otherwise, the user gets nothing. With enabled messaging the root user will get on his tty:
Message from TalkDaemon@his_machine...
talk: connection requested by your_name@your_machine.
talk: respond with: talk your_name@your_machine
So on the root console to reply back to talk chat request:
noah:~$ talk hipo@localhost
Tags: aim, Auto, auto mode, building, confnoah, daemon, deb, debian gnu, dependency, dependency tree, dgram, Disk, disk space, DoneBuilding, Draft, exec, Fetched, freebsd, gnu linux, information, Install, interactive user, localhost, login, mesg, noah, nobody, ntalk, ntalkd, operation, package, protocols, reading database, reading package, request, root, sbin, sessions, Shell, shell login, state information, tree, wait, work, writting
Posted in Linux | No Comments »
Thursday, April 19th, 2012
I'm doing replication for one server. Its not the first time I do configure replication between two MySQL database nodes, however since I haven't done it for a few years, my "know how" has mostly vanished so I had some troubles in setting it up. Once I followed some steps to configure replication I had to check if the two MASTER / Slave MySQL db nodes communicate properly. Hence I decided to drop a short post on that just in case if someone has to do the same or if I myself forget how I did it so I can check later on:
1. Check if MASTER MySQL server node is configured properly
The standard way to check a MySQL master node status info is with:
mysql> show master status;
+——————+———-+———————————————————+——————+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+——————+———-+———————————————————+——————+
| mysql-bin.000007 | 106 | database1,database2,database3 | |
+——————+———-+———————————————————+——————+
1 row in set (0.00 sec)
By putting \G some extra status info is provided:
mysql> show master status\G;
*************************** 1. row ***************************
File: mysql-bin.000007
Position: 106
Binlog_Do_DB: database1,database2,database3
Binlog_Ignore_DB:
1 row in set (0.00 sec)
ERROR:
No query specified
2. Check if Slave MySQL node is configured properly
To check status of the slave the cmd is:
mysql> show slave status;
The command returns an output like:
mysql> show slave status;+———————————-+————-+————-+————-+—————+——————+———————+————————-+—————+———————–+——————+——————-+——————————————————-+———————+——————–+————————+————————-+—————————–+————+————+————–+———————+—————–+—————–+—————-+—————+——————–+——————–+——————–+—————–+——————-+—————-+———————–+——————————-+—————+—————+—————-+—————-+| Slave_IO_State | Master_Host | Master_User | Master_Port | Connect_Retry | Master_Log_File | Read_Master_Log_Pos | Relay_Log_File | Relay_Log_Pos | Relay_Master_Log_File | Slave_IO_Running | Slave_SQL_Running | Replicate_Do_DB | Replicate_Ignore_DB | Replicate_Do_Table | Replicate_Ignore_Table | Replicate_Wild_Do_Table | Replicate_Wild_Ignore_Table | Last_Errno | Last_Error | Skip_Counter | Exec_Master_Log_Pos | Relay_Log_Space | Until_Condition | Until_Log_File | Until_Log_Pos | Master_SSL_Allowed | Master_SSL_CA_File | Master_SSL_CA_Path | Master_SSL_Cert | Master_SSL_Cipher | Master_SSL_Key | Seconds_Behind_Master | Master_SSL_Verify_Server_Cert | Last_IO_Errno | Last_IO_Error | Last_SQL_Errno | Last_SQL_Error |+———————————-+————-+————-+————-+—————+——————+———————+————————-+—————+———————–+——————+——————-+——————————————————-+———————+——————–+————————+————————-+—————————–+————+————+————–+———————+—————–+—————–+—————-+—————+——————–+——————–+——————–+—————–+——————-+—————-+———————–+——————————-+—————+—————+—————-+—————-+| Waiting for master to send event | HOST_NAME.COM | slave_user | 3306 | 10 | mysql-bin.000007 | 106 | mysqld-relay-bin.000002 | 251 | mysql-bin.000007 | Yes | Yes | database1,database2,database3 | | | | | | 0 | | 0 | 106 | 407 | None | | 0 | No | | | | | | 0 | No | 0 | | 0 | |+———————————-+————-+————-+————-+—————+——————+———————+————————-+—————+———————–+——————+——————-+——————————————————-+———————+——————–+————————+————————-+—————————–+————+————+————–+———————+—————–+—————–+—————-+—————+——————–+——————–+——————–+—————–+——————-+—————-+———————–+——————————-+—————+—————+—————-+—————-+
As you can see the output is not too readable, as there are too many columns and data to be displayed and this doesn't fit neither a text console nor a graphical terminal emulator.
To get more readable (more verbose) status for the SQL SLAVE, its better to use command:
mysql> show slave status\G;
Here is a sample returned output:
mysql> show slave status\G;*************************** 1. row *************************** Slave_IO_State: Waiting for master to send event Master_Host: HOST_NAME.COM Master_User: slave_user Master_Port: 3306 Connect_Retry: 10 Master_Log_File: mysql-bin.000007 Read_Master_Log_Pos: 106 Relay_Log_File: mysqld-relay-bin.000002 Relay_Log_Pos: 251 Relay_Master_Log_File: mysql-bin.000007 Slave_IO_Running: Yes Slave_SQL_Running: Yes Replicate_Do_DB: database1,database2,database3 Replicate_Ignore_DB: Replicate_Do_Table: Replicate_Ignore_Table: Replicate_Wild_Do_Table: Replicate_Wild_Ignore_Table: Last_Errno: 0 Last_Error: Skip_Counter: 0 Exec_Master_Log_Pos: 106 Relay_Log_Space: 407 Until_Condition: None Until_Log_File: Until_Log_Pos: 0 Master_SSL_Allowed: No Master_SSL_CA_File: Master_SSL_CA_Path: Master_SSL_Cert: Master_SSL_Cipher: Master_SSL_Key: Seconds_Behind_Master: 0Master_SSL_Verify_Server_Cert: No Last_IO_Errno: 0 Last_IO_Error: Last_SQL_Errno: 0 Last_SQL_Error: 1 row in set (0.00 sec)ERROR: No query specified
If show master status or shwo slave status commands didn't reveal replication issue, one needs to stare at the mysql log for more info.
Tags: Auto, Cipher, cmd, condition, configure, Connect, Draft, event, exec, host, info, key, Master, master node, master slave, mysql server, name, Path, quot, Replicate, replication, Retry, server node, show, slave status, someone, Space, SQL, time, User
Posted in MySQL, System Administration, Web and CMS | 4 Comments »
Saturday, April 7th, 2012
I've recently wanted to use PHP's embedded system(""); – external command execute function in order to use ls + wc to calculate the number of files stored in a directory. I know many would argue, this is not a good practice and from a performance view point it is absolutely bad idea. However as I was lazy to code ti in PHP, I used the below line of code to do the task:
<?
echo "Hello, ";
$line_count = system("ls -1 /dir/|wc -l");
echo "File count in /dir is $line_count \n";
?>
This example worked fine for me to calculate the number of files in my /dir, but unfortunately the execution output was also visialized in the browser. It seems this is some kind of default behaviour in both libphp and php cli. I didn't liked the behaviour so I checked online for a solution to prevent the system(); from printing its output.
What I found as a recommendations on many pages is instead of system(); to prevent command execution output one should use exec();.
Therefore I used instead of my above code:
<?
echo "Hello, ";
$line_count = exec("ls -1 /dir/|wc -l");
echo "File count in /dir is $line_count \n";
?>
By the way insetad of using exec();, it is also possible to just use ` (backtick) – in same way like in bash scripting's “.
Hence the above code can be also written for short like this:
<?
echo "Hello, ";
$line_count = `ls -1 /dir/|wc -l`;
echo "File count in /dir is $line_count \n";
?>
Tags: Auto, backtick, bad idea, behaviour, browser, code lt, command, command execution, count, default behaviour, dir, Draft, exec, execution, file, fine, function, idea, kind, libphp, line, online, order, performance, performance view, quot, solution, task, way
Posted in Programming, Web and CMS | 2 Comments »
Monday, February 13th, 2012
Does your camera show video correctly in cheese but shows captured video upside-down (inverted) in skype ?
This is an issue a friend of mine experienced on his Asus K51AC-SX037D laptop on both Ubuntu and Debian Linux.
As you can see in the picture above it is funny as with this bug the person looks like a batman
As the webcam upside-down issue was present on both latest Ubuntu 11.10 and latest stable Debian Squeeze 6.02, my guess was other GNU / Linux rpm based distro like Fedora might have applied a fix to this weird Skype inverted video (bat human like) issue.
Unfortunately testing the webcam with Skype on latest both Fedora 16 and Linux Mint 12 appeared to produce the same webcam bug.
A bit of research for the issue online and try outs of a number of suggested methods to resolve the issue led finally to a work around, thanks to this post
Here is few steps to follow to make the webcam show video like it should:
1. Install libv4l-0 package
root@linux:~# apt-get --yes install libv4-0
...
Onwards to start skype directly from terminal and test the camera type:
hipo@linux:~$ LD_PRELOAD=/usr/lib/libv4l/v4l1compat.so skype
This is the work around for 32 bit Linux install, most people however will probably have installed 64 bit Linux, for 64bit Linux installs the above command should be little different:
hipo@linux:~$ LD_PRELOAD=/usr/lib32/libv4l/v4l1compat.so skype
Once skype is launched test the camera and see if the camera capture is now uninverted, through menus:
S -> Options -> Video Devices -> Test
2. Create a skype Wrapper script Launcher
To make skype launch everytime with exported shell variable:
LD_PRELOAD=/usr/lib32/libv4l/v4l1compat.so
A new skype wrapper bash shell script should be created in /usr/local/bin/skype , the file should contain:
#!/bin/sh
LD_PRELOAD=/usr/lib32/libv4l/v4l1compat.so
/usr/bin/skype
To create the script with echo in a root terminal issue;
root@linux:~# echo '#!/bin/sh' >> /usr/local/bin/skype
root@linux:~# echo 'LD_PRELOAD=/usr/lib32/libv4l/v4l1compat.so' >> /usr/local/bin/skype
root@linux:~# echo '/usr/bin/skype' >> /usr/local/bin/skype
root@linux:~# chmod +x /usr/local/bin/skype
3. Edit the Skype gnome menu to substitute /usr/bin/skype Skype Launcher with /usr/local/bin/skype
Gnome 2 has a handy menu launcher, allowing to edit and add new menus and submenus (menus and items) to the Application menu, to launch the editor one has to click over Applications with last mouse button (right button) and choose Edit Menus
The menu editor like the one in the below screenshot will appear:
In the preceeding Launcher properties window, Command: skype has to be substituted with:
Command: /usr/local/bin/skype
For console freaks who doesn't want to bother in editting Skype Launcher via GUI /usr/share/applications/skype.desktop file can be editted in terminal. Inside skype.desktop substitute:
Exec=skype
with
Exec=/usr/local/bin/skype
As one can imagine the upside-down video image in Skype is not a problem because of Linux, but rather another bug in Skype (non-free) software program.
By the way everyone, who is using his computer with Free Software operating system FreeBSD, Linux etc. knows pretty well by experience, that Skype is a very problematic software; It is often a cause for system unexpected increased system loads, problems with (microphone not capturing), camera issues, issues with pulseaudio, problem with audio playbacks … Besides the long list of bugs there are unexpected display bugs in skype tray icon, bugs in skype messanger windows and at some rare occasions the program completely hangs and had to be killed with kill command and re-launched again.
Another worrying fact is Skype's versions available for GNU / Linux and BSD is completely out of date with its "competitor" operating systems MS Windows, MacOS X etc.
For people like me and my friend who want to use free operating system the latest available skype version is not even stable … current version fod download from skype's website is (Skype 2.2Beta)!
On FreeBSD the skype situation is even worser, freebsd have only option to run Skype ver 1.3 or v. 2.0 at best, as far as I know skype 2.2 and 2.2beta is not there.
Just as matter of comparison the latest Skype version on Windows is 5.x. Windows release is ages ahead its Linux and BSD ver. From a functional point of view the difference between Linux's 2.x and Windows 5.x is not that much different, what makes difference is is the amount of bugs which Linux and BSD skype versions contain…
Skype was about 6 months ago bought by Microsoft, therefore the prognosis for Skype Linux support in future is probably even darker. Microsoft will not probably bother to release new version of Skype for their competitor free as in freedom OSes.
I would like to thank my friend and brother in Christ Stelian for supplying me with the Skype screenshots, as well as for being kind to share how he fixed his camera with me.
Tags: Asus, Auto, bash shell script, batman, BSD, Button, camera capture, camera show, camera type, debian gnu, Desktop, distro, Draft, exec, fedora, file, gnu linux, gt options, hipo, laptop, launcher, ld, linux rpm, menu, Microsoft, person, PRELOAD, quot, root, root linux, rpm, Shell, show, Skype, software, squeeze, terminal, test, Ubuntu, ubuntu linux, video, video devices, web camera, webcam, work, wrapper script
Posted in Linux, Linux and FreeBSD Desktop, Skype on Linux | 18 Comments »
Tuesday, November 1st, 2011
My FreeBSD router has started running out of space, I looked for ways to clean up some space. So I remembered some programs are generating core files while they crash. Some of these files are really huge and ban be from 1Mb to > 1G.
I used find to first list all my produced core files starting from root directory (/) , like so:
find / -name core -exec du -hsc {} \;
....
Having a list of my core files with the respective core file size and after reviewing, I deleted one by one the cores which were there just taking up space.
It's a wise idea that core dumps file generation on program crash is completely disabled, however I forgot to disable cores, so I had plenty of the cores – (crash files which are handy for debug purposes and fixing the bug that caused the crash).
Further on I used an /etc/rc.conf – dumpdev=NO , variable which instructs the kernel to not generate core files on program crash:
freebsd# echo 'dumpdev=NO' >> /etc/rc.conf
Next, to make dumpdev=NO , take affect I rebooted the server:
freebsd# shutdown -r now
...
There is a way to instruct every server running daemon to know about the newly set dumpdev=NO by restarting each of the services with their init scripts individually, but I was too lazy to do that.
Tags: 1mb, ban, conf, confNext, core dump, core dumps, core files, cores, crash, DEBUG, dump, dumpdev, exec, file, freebsd, freebsd router, generation, hsc, idea, init, init scripts, kernel, list, name, obsolete program, plenty, program core, program crash, root, root directory, running out of space, shutdown, Space, taking up space, way, wise idea
Posted in FreeBSD, System Administration | No Comments »
Sunday, October 30th, 2011
Have you ever been in need to execute some commands scheduled via a crontab, every let's say 5 seconds?, naturally this is not possible with crontab, however adding a small shell script to loop and execute a command or commands every 5 seconds and setting it up to execute once in a minute through crontab makes this possible.
Here is an example shell script that does execute commands every 5 seconds:
#!/bin/bash
command1_to_exec='/bin/ls';
command2_to_exec='/bin/pwd';
for i in $(echo 1 2 3 4 5 6 7 8 9 10 11); do
sleep 5;
$command1_to_exec; $command2_to_exec;
done
This script will issue a sleep every 5 seconds and execute the two commands defined as $command1_to_exec and $command2_to_exec
Copy paste the script to a file or fetch exec_every_5_secs_cmds.sh from here
The script can easily be modified to execute on any seconds interval delay, the record to put on cron to use with this script should look something like:
# echo '* * * * * /path/to/exec_every_5_secs_cmds.sh' | crontab -
Where of course /path/to/exec_every_5_secs_cmds.sh needs to be modified to a proper script name and path location.
Another way to do the on a number of seconds program / command schedule without using cron at all is setting up an endless loop to run/refresh via /etc/inittab with a number of predefined commands inside. An example endless loop script to run via inittab would look something like:
while [ 1 ]; do
/bin/ls
sleep 5;
done
To run the above sample never ending script using inittab, one needs to add to the end of inittab, some line like:
mine:234:respawn:/path/to/script_name.sh
A quick way to add the line from consone would be with echo:
echo 'mine:234:respawn:/path/to/script' >> /etc/inittab
Of course the proper paths, should be put in:
Then to load up the newly added inittab line, inittab needs to be reloaded with cmd:
# init q
I've also red, some other methods suggested to run programs on a periodic seconds basis using just cron, what I found in stackoverflow.com's as a thread proposed as a solution is:
* * * * * /foo/bar/your_script
* * * * * sleep 15; /foo/bar/your_script
* * * * * sleep 30; /foo/bar/your_script
* * * * * sleep 45; /foo/bar/your_script
One guy, even suggested a shorted way with cron:
0/15 * * * * * /path/to/my/script
Tags: bashcommand, basis, com, command, command2, copy, copy paste, course, cron, crontab, echo 1, echo echo, endless loop, exec, file, foo, freebsd, gnu linux, init, inittab, interval, line, Linux, location, loop, mine, minute, name, nbsp, number, Path, predefined commands, pwd, record, refresh, respawn, script, script name, secs, SHA, Shell, shell script, sleep, something, stackoverflow, thread, time, time interval, way
Posted in Linux, Linux and FreeBSD Desktop, System Administration, Various | No Comments »
Friday, October 14th, 2011
After setupping a brand new Qmail installation following the QmailRocks Thibs Qmail Debian install guide , I've come across unexpected re-occuring error message in /var/log/qmail/qmail-smtpdssl/ , here is the message:
@400000004e9807b10d8bdb7c command-line: exec sslserver -e -vR -l my-mailserver-domain.com -c 30 -u 89 -g 89 \
-x /etc/tcp.smtp.cdb 0 465 rblsmtpd -r zen.spamhaus.org -r dnsbl.njabl.org -r dnsbl.sorbs.net -r bl.spamcop.net qmail-smtpd \
my-mailserver-domain.com /home/vpopmail/bin/vchkpw /bin/true 2>&1
@400000004e9807b10dae2ca4 sslserver: fatal: unable to load certificate
I was completely puzzled initially by the error as the sertificate file /var/qmail/control/servercert.pem was an existing and properly self generated one. Besides that qmail daemontools init script /service/qmail-smtpd/run was loading the file just fine, where the same file failed to get loaded when sslserver command with the cert argument was invoked via /service/qmail-smtpdssl/run
It took me quite a while to thoroughfully investigate on what's wrong with the new qmail install. Thanksfully after almost an hour of puzzling I found it out and I was feeling as a complete moron to find that the all issues was caused by incorrect permissions of the /var/qmail/control/servercert.pem file.
Here are the incorrect permissions the file possessed:
linux:~# ls -al /var/qmail/control/servercert.pem
-rw------- 1 qmaild qmail 2311 2011-10-12 13:21 /var/qmail/control/servercert.pem
To fix up the error I had to allow all users to have reading permissions over servercert.pem , e.g.:
linux:~# chmod a+r /var/qmail/control/servercert.pem
After adding all users readable bit on servercert.pem the file permissions are like so:
linux:~# ls -al /var/qmail/control/servercert.pem
-rw-r--r-- 1 qmaild qmail 2311 2011-10-12 13:21 /var/qmail/control/servercert.pem
Consequently I did a qmail restart to make sure the new readable servercert.pem will get loaded from the respective init script:
linux:~# qmailctl restart
* Stopping qmail-smtpdssl.
* Stopping qmail-smtpd.
* Sending qmail-send SIGTERM and restarting.
* Restarting qmail-smtpd.
* Restarting qmail-smtpdssl.
Now the annoying sslserver: fatal: unable to load certificate message is no more and all works fine, Hooray!
Tags: amp, argument, certificate, com, control, dae, dnsbl, error message, exec, file, gnu linux, guide, incorrect permissions, init, installation, Linux, log, moron, njabl, pem, pemTo, qmail installation, qmailctl, qmaild, QmailRocks, rblsmtpd, reading, rw 1, script, script service, sertificate, smtp, spamhaus, sslserver, Stopping, vr, zen
Posted in Linux, Qmail, System Administration | No Comments »
Wednesday, May 25th, 2011
I have a pirate version of Windows XP Pro 2 installer CD which does automatically turn on Windows Genuine Advantage
This is kind of annoying as the computer gets really slow and the hard disk drive activite gets intensive as well as an annoying popup message that the Windows XP copy is not genuine does appear periodically
In order to get rid of the message I had to do the following steps:
1. Get into Windows Safe Mode without Networking
As most of the people knows this is achieved by pressing F8 keyboard key right before the Windows bootup screen appears.
After in Safe mode it's necessery to,
2. Run Windows Command Line (cmd.exe)
To do so follow, the menus:
Windows (Start Menu) -> Run -> cmd.exe
3. In the command prompt window issue the commands:
C:\Documents and Settings\User> cd \Windows\System32
C:\Windows\System32> taskkill -IM wgatray.exe
C:\Windows\System32> del wgatray.exe
C:\Windows\System32> move wgalogon.dll wgalogon.dll.old
C:\Windows\System32> del wgalogon.dll.old
Something to mention is you have to be really quick, with deleting wgalogon.dll, cause wgatray.exe is scheduled to run every 1 / 2 seconds It is a bit of situation of type "be quick or be dead" as Maiden used to sing
A Windows system restart and Hooray the Windows Genuine message is gone
Tags: activite, Advantage, c documents, command, Computer, Disk, documents and settings, drive, exec, hard disk drive, issue, keyboard, kind, menu, menus, necessery, Networking, oldA, oldC, order, pirate version, popup, popup message, Start, taskkill, User, version, wgalogon, wgatray, windows command, windows safe mode, windows system, windows xp, windows xp copy, windows xp sp2
Posted in Windows | 1 Comment »
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