Category Archives: Tips

10 Must Have O’Reilly Books for System Administrators

Published several years ago these O’Reilly books are still useful & relevant for the current and new system administratiors. Although these books may not cover latest version of operating systems yet these explains very well the underlaying technical details and process which have not changed over the years.

awk Commands, Examples & Meaning

Learn to use awk for text and data extraction, data processing, validation,  generate reports for analysis, automation with with the help of examples of if else , compare & arrays plus regular expressions & built in operational variables, meaning, examples &command syntax.

Running Old Internet Explorer Based Applications in ie10

Windows Xp support is stopping on April 8, 2014 and one of the issues is that when you migrate to current Windows operating systems ( windows 8 ) old ie browsers are not supported for installation. Current OS Windows 8 comes with ie 10 and older versions of ie are not supported.
The biggest problem is that many of corporate applications which are designed long back and no longer supported may still need older ie 7 , 8 or 9

Linux & Unix Date Format Examples

Learn about Linux and Unix date & time formating with the help of simple explanation and added example. Date command in Unix & Linux is used to format date as well as time. First portion of this article covers Date  function and the second portion has the  time function covered.

Php Date Format

Date time formatting in PHP
Many scripts written in php need date and time function . PHP has many predfined date formats and you can also customized it as per your need .
Here are some of the date format examples and additional details for php.

ssh Without Password in Few Simple Steps

How to configure passwordless ssh &sftp access in Unix & Linux systems? Follow these simple steps with examples with a basic troubleshooting section at the end. sftp uses underlaying ssh access for authentication and after you establish passwordless ssh access you will have passwordless sftp access as well.

This a real life example of configuring passwordless access for two users . The user ‘web’ in this case needs a secure password less access to another user james in a server ‘devserver’
.

Crontab – Quick Reference

Setting up cron jobs in Unix, Solaris & Linux

cron is a unix, solaris, Linux utility that allows tasks to be automatically run in the background at regular intervals by the cron daemon. 

Unix Commands Tutorial

Learn about the Unix commands with their usages and examples.
This Unix command tutorial introduces you with some of the most popular and useful commands used in nix operating system to get you started with Unix.
All Unix OS comes with online manual system, man, which can be used used as ,man , to get more details and complete set of options.

Unix Tech Tips

  1. Running Sol
    aris  in 32 or 64 bit mode
    – Page 1
  2. Removing ^M from Unix text files – Page 2
  3. Backup commands – ufsdump , tar , cpio – Page 3
  4. Setting up Ethernet card speed & duplex mode – Page 4
  5. One Line scripts – Page 4

DNS Troubleshooting

DNS troubleshooting , this article describes some of the common dns problems and their solutions.
First phase of article describes dns errors relating to configuration , server setup and its basic functionality . Second phase talks about the nslookup related errors when the dns servers seems to be working correctly but names resolution fail .

fsck – Check & Repair Unix and Linux File Systems

fsck, similar to chkdsk in windows, checks and repairs the file system in Unix & Linux operating systems. Learn about fsck modes, phases & fsck errors messages

fsck, File System Consistency checK, is a system utility in Unix, Linux and other Unix like systems for checking and repairing file system inconsistencies.

File system can become inconsistent due to several reasons and the most common is abnormal shutdown due to hardware failure, power failure or switching off the system without proper shutdown. Due to these reasons the superblock in a file system is not updated and has mismatched information relating to system data blocks, free blocks and inodes.

fsck in Linux

fsck in this document is refered with reference to ufs file system but it can be used in Linux systems as

fsck -t ext2 /dev/sda3
or
fsck.ext2 /dev/sda3
fsck.ext4 /dev/sda3
fsck.ext3 /dev/sda3

it returns with any of the followig code

0 – No errors
1 – File system errors corrected
2 – System should be rebooted
4 – File system errors left uncorrected
8 – Operational error
16 – Usage or syntax error
32 – Fsck canceled by user request
128 – Shared library error

fsck checks the file systems defined in /etc/fstab in Linux and /etc/vfstab in Unix systems