Let’s say you are running a data restore. Things are moving along, but network is congested and the backup server is overloaded. You really don’t feel staring at the restore status for the next several hours and just want to be notified when the process completes. The simplest method of monitoring for processes starting or ending on Unix systems is by using “ps” with a “while” loop.

Imagine a hypothetical scenario: you support hundreds of remote servers and you need to check which server you can access via SSH and which servers are not letting you log in. Doing this manually is a tedious process that many sysadmins choose to skip. The inevitable outcome is inability to quickly access a system when it really counts.

Sometimes you don’t want people to reach you on your phone, but you don’t want to do something obvious, like turning the phone off. Because then they’ll just leave you a message and you will still be expected to call back. Below is a list of phone number in various US area codes that you can use to forward your unwanted calls.

The Unix “man” pages are an indispensable tool even for the most experienced of sysadmins. Unfortunately, in a terminal window the text may be hard to read and getting a hard copy to take with you down to the datacenter will really test your Unix skills. The following quick script will convert the “man” page of your choice into formatted text and open it in the Web browser.

A common real-life scenario: on a multi-CPU system Oracle processed have taken over and the system has ground to a crawl. The average system load is in double-digits and even logging in takes several minutes. The possible root causes for the problem can range from inefficient SQL queries (the common problem) to insufficient system resources. But at this point you just need to make the system a bit more responsive, so you can start troubleshooting.

We have discussed using expect with sudo in an SSH session. Another common way to run commands on remote servers as root is to use the su – root command, where sudo is not configured. The trick to automating su operations using expect is to launch the su command with the spawn ssh command.

In this example we will show you how to calculate simple moving average using Excel and a shell script. As more data is added to the file, the shell script and the Excel formula will automatically use the specified number of the latest data points to calculate the moving average.

Let’s imagine a hypothetical scenario: you have a list of a hundred Linux servers and you need to log into each one of them and remove a local user “roger” and his home directory. Doing this by hand will get tedious and, chances are, you will make a few typos and there will be some collateral damage.

The idea here is simple: you need to connect to hosts 1..100 and execute a command in the background. The trick is to make sure the command continues to run after the SSH session terminates. Simply adding the “&” at the end of the command is not the answer here.

Just a quick alert: the latest version (v. 3.0.3.3) of the popular Shadowbox JS plugin for WordPress has a serious bug that exposes your WordPress installation to a major security risk. Incorrectly coded handling of the “player” tag causes all of your NexGEN Gallery images to be displayed on any page that also has single images embedded via WordPress “Add an Image” function.

Recently I’ve ran into an unusual problem with SSH on SLES 11 SP1. The system – a small HPC cluster – is configured to use NIS for authentication and automounter maps. Whenever a user logs in, the home directory is automounted from an external NAS. Each user has a ~/.ssh directory with the authorized_keys2 and known_hosts required for password-less SSH access among the cluster nodes.