Category Archives: Operating System

About the /proc and -xdev parameter for ‘find’

/proc is a pseudo-filesystem used to access process information from the kernel. It doesn’t use any storage space and uses little memory. On Linux, you can sometimes make modifications to the running kernel by modifying “files” in /proc. If / is full, run a command similar to the following to sort all files in the … Continue reading

Difference Between NFS, DNS, NIS+, and NIS

NFS, DNS, NIS and NIS+… that’s a lot of acronyms! Network File System NFS is Sun’s Networked File System, and by now, more or less, the de facto method of sharing file systems between computers. Domain Name Service DNS is the Domain Name Service, which is the way information about hostnames and addresses are shared … Continue reading

UNIX Quick Tip: Changing The Time Stamp Of A File

This tip is a give away. Everyone knows this, but for those who doesn’t or forgot…  here’s refresher… Here’s a typical output of a file listing using `ls -l` on a directory: [root@unix-box icons]# ls -l | more total 636 -rw-r–r–    1 elizar root          246 Aug 26  2005 a.gif -rw-r–r–    1 elizar root          242 Aug … Continue reading

Monitoring User Logins In UNIX

Here are some of the commands and files that you may want to check out if you want to monitor your users’ login activity on a Unix box (BSD/Solaris) The concerned files (Solaris): /var/adm/utmp(x) /var/adm/wtmp(x) /var/adm/lastlog The Commands: users* who w ac* last *may not be available in Solaris? All sample outputs show on this … Continue reading

Loop Kill Mutiple PID On Bourne Shell

Just want to document it here. A colleague request to kill multiple PID owned by different users. They don’t have any special privilege to kill process other than their own. Here’s a simple for…loop script that will look for and kill each PID it found. #!/bin/sh -x ps -ef | grep nobody | awk ‘{print … Continue reading

Checking and Repairing File system with fsck

fsck is the command used in UNIX for checking filesystem for any inconsistencies, usually caused by abnormal shutdown. These abnormal shutdown may be caused by some hardware failure or power failure. fsck also has options to repair filesystem as well. Syntax: fsck  [ -F fstype]  [-V]    [-yY]    [-o options]  special -F fstype     type of file system … Continue reading

Set Up Environment Variable on Bourne, Bash, Korn and C-Shells

There are many shells available for the UNIX operating system. Among them are sh (bourne), csh (C), tsch (korn) and bash (bourne again) Shells. With all these shells, sometimes we can mix all the syntax when assigning values to a variables. Here’s is another review so you wont forget: C Shell (csh) or Korn (tcsh): … Continue reading

SCO Group (SCO UNIX) Is Bankrupt!

Santa Cruz Operation SCO Group, the same group that gave us SCO UNIX has filed bankruptcy last Friday. That is bad news not only for the SCO users and community but for the stock holders too! The bankruptcy that was filed was The Chapter 11 Bankruptcy! Meaning, the court will take over (with the creditor’s … Continue reading

The getent Command

For the UNIX side of things, we’ll try to feature one command a week that is commonly used in system/user administration on a UNIX box. If anyone wants to contribute more, then we may do one command every two days or ‘Unix Command for the day’. Something like that. For today, it’s all about getent. … Continue reading

OpenLDAP Installation on Sun Blade 100

This is an OpenLDAP installation on the following system: System Configuration: Sun Microsystems sun4u Memory size: 1024 Megabytes Sun-Blade-100 (UltraSPARC-IIe) Prerequisites: Depending on the requirements, there may be a need to install some third party softwares: OpenSSl Kerberos SASL Berkeley DB TCP Wrappers and others Need to make sure the following variables is set: Variable … Continue reading