sorted by: recent | see :
popular
Content Tagged with OpenSolaris + Unix
SunHelp.Ru Русская документация по Solaris, Sun
Описание DTrace, ZFS, Solaris Zones и других возможностей Solaris
Solaris 10: советы и приёмы системного администрирования
Как пользоваться DTrace, ZFS, Solaris Zones и другими технологиями Solaris
Setup Mail Client on UNIX-based System
In the last post, a mail server setup was demonstrated. This post will demonstrate the setup of a mail client. Again, the setup of mail client is fairly straightforward. Here is the run.
On the client side, ensure the /var/mail directory is present.
# ls -l /var/mail
If not, create it.
# cd /var
# mkdir mail
Now modify the client's /etc/vfstab file
# vi /etc/vfstab
esoft:/var/mail - /var/mail nfs - yes -
:wq!
Now mount /var/mail
# mount /var/mail
Verify the /var/mail is actually being shared from the mail server
# cd /var/mail
# df -k .
On the client side, ensure the /var/mail directory is present.
# ls -l /var/mail
If not, create it.
# cd /var
# mkdir mail
Now modify the client's /etc/vfstab file
# vi /etc/vfstab
esoft:/var/mail - /var/mail nfs - yes -
:wq!
Now mount /var/mail
# mount /var/mail
Verify the /var/mail is actually being shared from the mail server
# cd /var/mail
# df -k .
Finding Open Files with lsof Command
When a file is in use by a process, it is possible to delete the file - OR at least it may appear that is the case. The filename is no longer visible via the ls command, but it is there until the process using it exits.
For example, let's say Sysadmin1 runs a sniffer process in the background to capture and save packets to a file. The capture file starts growing bigger over time. Instead of killing the process, he/she simply deletes the capture file, thinking this will recover the disk space. It doesn't. Believing everything is well, Sysadmin1 goes home.
Now Sysadmin2 shows up and notices the box is running out of disk space. Naturally, the admin wants to figure out what’s rapidly consuming disk space. The easiest way for the SysAd to locate the growing file is to use the lsof command.
Another instance the lsof would be helpful is when a filesystem refuses to unmount due to open files.
Here are a few practical examples of using the lsof command.
To list all the open files on the var filesystem:
# lsof +D /var
To list all open files in your current directory only:
# lsof +d .
To list all open Internet files:
# lsof -i
To list all files currently open by user joe:
# lsof -u joe
To list all files open by syslog-ng (this is a great quick way to find
logs!):
# lsof -c syslog-ng
To list all files open by pid:
# lsof -p PID
Note: There are additional parameters you can add to the command to narrow the listing to include or exclude types of files and much more!
# lsof -help
Post provided by Mary M. Chaddock
For example, let's say Sysadmin1 runs a sniffer process in the background to capture and save packets to a file. The capture file starts growing bigger over time. Instead of killing the process, he/she simply deletes the capture file, thinking this will recover the disk space. It doesn't. Believing everything is well, Sysadmin1 goes home.
Now Sysadmin2 shows up and notices the box is running out of disk space. Naturally, the admin wants to figure out what’s rapidly consuming disk space. The easiest way for the SysAd to locate the growing file is to use the lsof command.
Another instance the lsof would be helpful is when a filesystem refuses to unmount due to open files.
Here are a few practical examples of using the lsof command.
To list all the open files on the var filesystem:
# lsof +D /var
To list all open files in your current directory only:
# lsof +d .
To list all open Internet files:
# lsof -i
To list all files currently open by user joe:
# lsof -u joe
To list all files open by syslog-ng (this is a great quick way to find
logs!):
# lsof -c syslog-ng
To list all files open by pid:
# lsof -p PID
Note: There are additional parameters you can add to the command to narrow the listing to include or exclude types of files and much more!
# lsof -help
Post provided by Mary M. Chaddock
IT Certification Self-Help Portal
I found this technical self-help website, uCertify.com, very interesting and wanted to share it with some of the readers. The company has been online since 1999. They are offering PrepKits which are interactive software programs that help you learn, track your progress, identify areas for improvement and simulate the actual exam. I sampled a few of their demo quizzes, but I mainly focused on their database kits because I am thinking about an Oracle certification in the near-term. On my initial run through, I found the practice test questions to be relevant and comprehensive, not just some cheesy Q&A effort.
I downloaded their Oracle 10G kit and obtained a key for it. It was a quick download via VDSL and was extremely easy to setup. I did not have any problems obtaining a key from uCertify. For the premium version, I took a couple of its timed practice tests along with its timed final. I thought the final test was a bit more difficult than the practice tests which was probably by design. Also, I noticed there was a “learn” function for each test question, which was accompanied by a thorough explanation. Frankly speaking, I needed to use a “RE-learn” function on some of the questions. :) There was also a means to create your own tests, add your own questions, provide immediate feedback, tagging, print, review questions, and make notes online – this flexibility was a nice surprise.
One last thing, per their website, they say if you do not pass the certification on your first attempt, they will refund your money. Yes, I was looking for an asterisk after this statement and was pleasantly surprised not to find one.
Here is what you get with the sample version.
30 questions total (this includes the quiz questions)
30 diagnostic test questions
Create tests
22 study notes
Articles, HOWTO's, and study tips
Progress report
Here is an example of what you get with the premium version, which may vary from kit to kit.
301 test questions
3 full length practice tests
105 study notes
Create tests
Unlimited free upgrades for a period of one year from the date of purchase
24x7 technical services
100% money back guarantee
Articles, HOWTO's, and study tips
Provide discounts on all future purchases
The sample version did give me a decent idea of what the tests were all about. Their PrepKits are designed to help you certify on vendors such as Microsoft, Cisco, Oracle, Adobe and a few others.
By the way, this is NOT a paid post.
If you are interested in a free, fully functional certification kit of your choice, leave a helpful non-anonymous UNIX-related HOWTO comment here and I will choose a winner after about two weeks. This is a $10 to $100+ value depending on the selected kit.
Update from uCertify: Your readers can use our discount code given on your Blog and get 10% discount on the uCertify PrepKit of their choice. Please use the following Discount code: ESOHUB
I downloaded their Oracle 10G kit and obtained a key for it. It was a quick download via VDSL and was extremely easy to setup. I did not have any problems obtaining a key from uCertify. For the premium version, I took a couple of its timed practice tests along with its timed final. I thought the final test was a bit more difficult than the practice tests which was probably by design. Also, I noticed there was a “learn” function for each test question, which was accompanied by a thorough explanation. Frankly speaking, I needed to use a “RE-learn” function on some of the questions. :) There was also a means to create your own tests, add your own questions, provide immediate feedback, tagging, print, review questions, and make notes online – this flexibility was a nice surprise.
One last thing, per their website, they say if you do not pass the certification on your first attempt, they will refund your money. Yes, I was looking for an asterisk after this statement and was pleasantly surprised not to find one.
Here is what you get with the sample version.
30 questions total (this includes the quiz questions)
30 diagnostic test questions
Create tests
22 study notes
Articles, HOWTO's, and study tips
Progress report
Here is an example of what you get with the premium version, which may vary from kit to kit.
301 test questions
3 full length practice tests
105 study notes
Create tests
Unlimited free upgrades for a period of one year from the date of purchase
24x7 technical services
100% money back guarantee
Articles, HOWTO's, and study tips
Provide discounts on all future purchases
The sample version did give me a decent idea of what the tests were all about. Their PrepKits are designed to help you certify on vendors such as Microsoft, Cisco, Oracle, Adobe and a few others.
By the way, this is NOT a paid post.
If you are interested in a free, fully functional certification kit of your choice, leave a helpful non-anonymous UNIX-related HOWTO comment here and I will choose a winner after about two weeks. This is a $10 to $100+ value depending on the selected kit.
Update from uCertify: Your readers can use our discount code given on your Blog and get 10% discount on the uCertify PrepKit of their choice. Please use the following Discount code: ESOHUB
System
Unix
Administration
OpenSolaris
Windows
oracle
tutorials
Troubleshoot POP3 Mail Server with Telnet
I am finally getting an opportunity to write a post. I have been so busy with upgrades lately and had to put off writing for awhile.
The other day I had a number of users complaining about not being able to fetch mail to their mail client, MS Outlook. As usual, I attempted to duplicate the error. The error message was reporting unable to connect to the mail server. At that point, I decided to telnet the Post Office Protocol or POP3 port, 110, via the command line interface. Sure enough, I had a problem.
Note: The “before and after” command line examples are only for illustration purposes.
# telnet server 110
Trying 192.1xx.xx.xxx...
telnet: Unable to connect to remote host: Connection refused
I started thinking there was a problem with the inetd.conf file. After reviewing the file, I noticed the pop3 service was commented out. The appropriate change was made and inetd was restarted. Problem resolved.
# telnet server 110
Trying 192.1xx.xx.xxx...
Connected to server.
Escape character is '^]'.
+OK connected to pop3 on 3429
By the way, you can check out other popular port services, too.
# telnet server 6667
# telnet server 25
The other day I had a number of users complaining about not being able to fetch mail to their mail client, MS Outlook. As usual, I attempted to duplicate the error. The error message was reporting unable to connect to the mail server. At that point, I decided to telnet the Post Office Protocol or POP3 port, 110, via the command line interface. Sure enough, I had a problem.
Note: The “before and after” command line examples are only for illustration purposes.
# telnet server 110
Trying 192.1xx.xx.xxx...
telnet: Unable to connect to remote host: Connection refused
I started thinking there was a problem with the inetd.conf file. After reviewing the file, I noticed the pop3 service was commented out. The appropriate change was made and inetd was restarted. Problem resolved.
# telnet server 110
Trying 192.1xx.xx.xxx...
Connected to server.
Escape character is '^]'.
+OK connected to pop3 on 3429
By the way, you can check out other popular port services, too.
# telnet server 6667
# telnet server 25
Using Z Shell Brace Expansion to Create Test Files
Here is a convenient way of creating test files using the powerful Z Shell. I have been using this shell for a short while, and I am quickly becoming a fan of it. I used it to support transfer speed tests. To support these tests, I created a specified number of files that varied in size (1MB, 5MB, 10MB, 50MB, 100MB, 500MB, etc). Here is a straightforward one-liner mkfile example of creating 50 x 12MB files and a few others using zsh’s brace expansion.
# zsh
# mkfile 12m {1..50}.tst
# ls -l
total 122960
-rw------T 1 root other 12582912 Feb 18 20:04 1.tst
-rw------T 1 root other 12582912 Feb 18 20:04 2.tst
-rw------T 1 root other 12582912 Feb 18 20:04 3.tst
-rw------T 1 root other 12582912 Feb 18 20:04 4.tst
-rw------T 1 root other 12582912 Feb 18 20:04 5.tst
...
Other examples...
# touch {1..5}.testfile
# ls -l
total 0
-rw-r--r-- 1 root other 0 Feb 18 20:07 1.testfile
-rw-r--r-- 1 root other 0 Feb 18 20:07 2.testfile
-rw-r--r-- 1 root other 0 Feb 18 20:07 3.testfile
-rw-r--r-- 1 root other 0 Feb 18 20:07 4.testfile
-rw-r--r-- 1 root other 0 Feb 18 20:07 5.testfile
# touch {6..10}.data
# ls -l
total 0
-rw-r--r-- 1 root other 0 Feb 18 20:30 1.data
-rw-r--r-- 1 root other 0 Feb 18 20:30 10.data
-rw-r--r-- 1 root other 0 Feb 18 20:30 2.data
-rw-r--r-- 1 root other 0 Feb 18 20:30 3.data
-rw-r--r-- 1 root other 0 Feb 18 20:30 4.data
-rw-r--r-- 1 root other 0 Feb 18 20:30 5.data
-rw-r--r-- 1 root other 0 Feb 18 20:30 6.data
-rw-r--r-- 1 root other 0 Feb 18 20:30 7.data
-rw-r--r-- 1 root other 0 Feb 18 20:30 8.data
-rw-r--r-- 1 root other 0 Feb 18 20:30 9.data
# ls -l {1..5}.data
-rw-r--r-- 1 root other 0 Feb 18 20:26 1.data
-rw-r--r-- 1 root other 0 Feb 18 20:26 2.data
-rw-r--r-- 1 root other 0 Feb 18 20:26 3.data
-rw-r--r-- 1 root other 0 Feb 18 20:26 4.data
-rw-r--r-- 1 root other 0 Feb 18 20:26 5.data
# zsh
# mkfile 12m {1..50}.tst
# ls -l
total 122960
-rw------T 1 root other 12582912 Feb 18 20:04 1.tst
-rw------T 1 root other 12582912 Feb 18 20:04 2.tst
-rw------T 1 root other 12582912 Feb 18 20:04 3.tst
-rw------T 1 root other 12582912 Feb 18 20:04 4.tst
-rw------T 1 root other 12582912 Feb 18 20:04 5.tst
...
Other examples...
# touch {1..5}.testfile
# ls -l
total 0
-rw-r--r-- 1 root other 0 Feb 18 20:07 1.testfile
-rw-r--r-- 1 root other 0 Feb 18 20:07 2.testfile
-rw-r--r-- 1 root other 0 Feb 18 20:07 3.testfile
-rw-r--r-- 1 root other 0 Feb 18 20:07 4.testfile
-rw-r--r-- 1 root other 0 Feb 18 20:07 5.testfile
# touch {6..10}.data
# ls -l
total 0
-rw-r--r-- 1 root other 0 Feb 18 20:30 1.data
-rw-r--r-- 1 root other 0 Feb 18 20:30 10.data
-rw-r--r-- 1 root other 0 Feb 18 20:30 2.data
-rw-r--r-- 1 root other 0 Feb 18 20:30 3.data
-rw-r--r-- 1 root other 0 Feb 18 20:30 4.data
-rw-r--r-- 1 root other 0 Feb 18 20:30 5.data
-rw-r--r-- 1 root other 0 Feb 18 20:30 6.data
-rw-r--r-- 1 root other 0 Feb 18 20:30 7.data
-rw-r--r-- 1 root other 0 Feb 18 20:30 8.data
-rw-r--r-- 1 root other 0 Feb 18 20:30 9.data
# ls -l {1..5}.data
-rw-r--r-- 1 root other 0 Feb 18 20:26 1.data
-rw-r--r-- 1 root other 0 Feb 18 20:26 2.data
-rw-r--r-- 1 root other 0 Feb 18 20:26 3.data
-rw-r--r-- 1 root other 0 Feb 18 20:26 4.data
-rw-r--r-- 1 root other 0 Feb 18 20:26 5.data
Troubleshooting the "su: No shell" error
The other day we had a problem with a system account. At first we did not notice the “su: No shell” error on the console (headless server) but after a few reboots it was fairly evident. The message gave us enough feedback to determine the substitute user or su command was having a problem with a particular account. To ascertain which system account, we invoked a sequential step-through of the startup scripts.
In the end, it appears that a third party application used to manage NIS+ had locked and changed the account’s shell to something unknown (by design) due to multiple login failures. The account was restored to its original shell.
# su - esofthub -c "myscript"
su: No shell
View locked account
# niscat passwd.org_dir | grep esofthub
esofthub:*LK*:1005:10:esofthub test:/home/esofthub:/bin/sh.locked:13933::::::
Modify with third party application
After the modification
# su - esofthub -c "myscript"
Visit Ucertify's challenge winners' blogs: Ax0N and armando
For Files Only
If you are using the files repository and no third party software to manage your user information, modify the /etc/passwd file.
View locked account
# less /etc/shadow | grep esofthub
esofthub:*LK*:13933::::::
# less /etc/passwd | grep esofthub
esofthub:x:1005:10:esofthub test:/home/esofthub:/bin/sh.locked
Modify the account manually or admintool
# vi /etc/passwd
...
esofthub:x:1005:10:esofthub test:/home/esofthub:/bin/sh
...
:wq!
Change shell to C shell or any other shell if so desired
# passwd -r files -e esofthub
Old shell: /bin/sh
New shell: /bin/csh
Or
# admintool &
After the modification
# su - esofthub -c "myscript"
Visit Ucertify's challenge winners' blogs: Ax0N and armando
In the end, it appears that a third party application used to manage NIS+ had locked and changed the account’s shell to something unknown (by design) due to multiple login failures. The account was restored to its original shell.
# su - esofthub -c "myscript"
su: No shell
View locked account
# niscat passwd.org_dir | grep esofthub
esofthub:*LK*:1005:10:esofthub test:/home/esofthub:/bin/sh.locked:13933::::::
Modify with third party application
After the modification
# su - esofthub -c "myscript"
Visit Ucertify's challenge winners' blogs: Ax0N and armando
For Files Only
If you are using the files repository and no third party software to manage your user information, modify the /etc/passwd file.
View locked account
# less /etc/shadow | grep esofthub
esofthub:*LK*:13933::::::
# less /etc/passwd | grep esofthub
esofthub:x:1005:10:esofthub test:/home/esofthub:/bin/sh.locked
Modify the account manually or admintool
# vi /etc/passwd
...
esofthub:x:1005:10:esofthub test:/home/esofthub:/bin/sh
...
:wq!
Change shell to C shell or any other shell if so desired
# passwd -r files -e esofthub
Old shell: /bin/sh
New shell: /bin/csh
Or
# admintool &
After the modification
# su - esofthub -c "myscript"
Visit Ucertify's challenge winners' blogs: Ax0N and armando
SSH Secure Shell for Workstations
A few years ago I took an Oracle database class at a university. I remember running SQL commands to perform a number of DBA tasks, such as creating databases, creating tables, creating procedures, altering tables, etc. via the command line. But in order to complete these tasks, we had to connect to the university's UNIX server via SSH. I remember using a nifty ssh client application. I found a link to its website while browsing my old coursework archive. At the time, I downloaded the "university use" copy, which was free, and it worked pretty well for the course.
Per the vendor's website, you can still download their SSH Secure Shell 3.2 non-commercial source code and there is also a Windows Client executable. Both are free of charge from various anonymous ftp sites around the globe for purposes of EVALUATION, NON-COMMERCIAL USE, and UNIVERSITY USE as defined in their license agreement.
Here is the link to the SSH Secure Shell for Workstations.
Other suggestions are always welcome.
Per the vendor's website, you can still download their SSH Secure Shell 3.2 non-commercial source code and there is also a Windows Client executable. Both are free of charge from various anonymous ftp sites around the globe for purposes of EVALUATION, NON-COMMERCIAL USE, and UNIVERSITY USE as defined in their license agreement.
Here is the link to the SSH Secure Shell for Workstations.
Other suggestions are always welcome.
Free Anti-virus Software Solution
If you are like me, you are always searching for ways to protect your personal computer. Probably, the first thing that comes to mind is viruses and worms.
Along with millions of other AVG users, I have been using their free anti-virus software version off and on since 1997. Usually, when something is for free, you get what you paid for - sub par performance. But with AVG, I can't complain too much about their free non commercial anti-virus solution. Why? It has been easy to use, consumes low system resources, automatic update functionality and provides real time protection. If you want more services, such as anti-spyware, anti-rootkit, anti-spam, firewall, web shield or 24/7 support, you will have to pay for them. The free version supports most Windows and Linux platforms. As usual, this is not a paid post and other free anti-virus solutions/suggestions are welcome.
Note: Per AVG's website: AVG Anti-Virus Free is only available for single computer use for home and non commercial use - for platform compatibility.
Along with millions of other AVG users, I have been using their free anti-virus software version off and on since 1997. Usually, when something is for free, you get what you paid for - sub par performance. But with AVG, I can't complain too much about their free non commercial anti-virus solution. Why? It has been easy to use, consumes low system resources, automatic update functionality and provides real time protection. If you want more services, such as anti-spyware, anti-rootkit, anti-spam, firewall, web shield or 24/7 support, you will have to pay for them. The free version supports most Windows and Linux platforms. As usual, this is not a paid post and other free anti-virus solutions/suggestions are welcome.
Note: Per AVG's website: AVG Anti-Virus Free is only available for single computer use for home and non commercial use - for platform compatibility.
System
Software
Unix
Administration
OpenSolaris
Anti-Virus
solution
Home - Nexenta Project Wiki
opensolaris distro that includes ZFS
Curriculum Development Resources at OpenSolaris.org
These resources are intended both to educate about OpenSolaris and to facilitate computer science education in general. We are constantly adding to these materials, and any contribution, feedback or other input is always welcom
opensource: del.icio.us tag/opensource
Development
Documentation
Kernel
Unix
OpenSolaris
solaris
Guide
Page 1 | Next >>