Services That Can Be Turned Off in a CentOS 6, Minimal Server

Posted on by rchapin

Following is a list of services that can (for most applications) be turned off if you are setting up a bare-bones CentOS 6.4 server:

Automatic bug reporting services:
abrt-ccpp
abrt-oops
abrtd

Power control and features, query battery and config status
acpid

Controls ‘at’ command queing, examining, or deleting jobs for later execution.  Anything atd can do, cron can do
atd

File auditing
auditd

Auto fs mounting
autofs

Printing
cups

For desktop environments:
netfs

Network filesystems:
nfslock
rpcbind
rpcgssd
rpcidmapd

MTA→ Continue reading “Services That Can Be Turned Off in a CentOS 6, Minimal Server”

Setting Up Passwordless SSH Under CentOS 6 Running Selinux

Posted on by rchapin

I am setting up a cluster of KVM virtual machines and want to be able to ssh to them as the root user on the vm without having to enter a password.

The first thing that I did was create keys on the box from which I was going to make connections (A):

[rchapin@A .ssh]$ ssh-keygen
Generating public/private rsa key pair.
Enter file in which to save the key (/usr/local2/home/rchapin/.ssh/id_rsa):
Enter passphrase (empty for no passphrase):
Enter same passphrase again: → Continue reading “Setting Up Passwordless SSH Under CentOS 6 Running Selinux”

jsbeautifier.org: Beautify, unpack or deobfuscate JavaScript and HTML, make JSON/JSONP readable, etc.

Posted on by rchapin

The title of this entry is straight from the http://jsbeautifier.org/ website and says it all.→ Continue reading “jsbeautifier.org: Beautify, unpack or deobfuscate JavaScript and HTML, make JSON/JSONP readable, etc.”

Splitting a String into an Array with a Custom Delimiter in a Bash Shell Script

Posted on by rchapin

Most high level languages have some sort of String.split([delimiter]) method to create an array of Strings tokenized by a user specified delimiter.  This is a simple way to convert a CSV into an array.

Here is a quick way to do that in a bash shell script:

#!/bin/bash

SOURCE_STRING='foo|blah|moo'
# Save the initial Interal Field Separator
OIFS="$IFS"
# Set the IFS to a custom delimiter
IFS='|'

read -a TOKENS <<< "${SOURCE_STRING}"
for i in "${TOKENS[@]}"
do
  echo "$i"
done

#
→ Continue reading “Splitting a String into an Array with a Custom Delimiter in a Bash Shell Script”

Running VisualVM to Examine a JVM on a Remote Host Via an SSH Tunnel/Proxy Connection

Posted on by rchapin
VisualVM is a great tool for peering into a running JVM.  In many cases, it won’t be one that is running on your local box.
The first thing to be done is to get jstatd running on the remote machine:
Create a security policy file on the remote machine (this assumes that you have an additional layer of security and that the outside world cannot access these ports and/or you have a VPN set-up and you are operating in that
→ Continue reading “Running VisualVM to Examine a JVM on a Remote Host Via an SSH Tunnel/Proxy Connection”

Setting up an HTTP Proxy over SSH in Chrome under Fedora Core 18 Linux

Posted on by rchapin

At least under the FC 18 distro, there was no fancy GUI controls in the Advanced Settings for setting up an HTTP proxy over SSH for Chrome.

To get it all set up:

  • Establish and ssh connection to the server to which you want to proxy:
    • $ ssh -D localhost:1234 username@remote.server,  where 1234 is the port number you want to use for the proxy
  • Run google-chrome from the command line passing it the proxy setting:
    • $ google-chrome –proxy-server=socks5://localhost:1234
→ Continue reading “Setting up an HTTP Proxy over SSH in Chrome under Fedora Core 18 Linux”

Screen Cheat Sheet

Posted on by rchapin

I have recently be introduced to the *nix screen command.  Incredibly powerful tool for managing windows which mulitplexes a physical terminal between one or many processes.  One of the uses it to maintain interactive shells on a remote server between remote connections to the machine.

It is enormously helpful when executing long running commands on remote servers.  Especially those that timeout your ssh connection and or from machines that you are going to either disconnect from the net or shutdown.→ Continue reading “Screen Cheat Sheet”

Quick and Dirty HTTP Server to Transfer Files

Posted on by rchapin

If you need to stand up a quick HTTP Server to enable someone on your LAN to transfer some files use the following command in the directory that you want to ‘share’:

python -m SimpleHTTPServer

The default port is 8000, but you can run it as follows to specify a port

python -m SimpleHTTPServer 8080→ Continue reading “Quick and Dirty HTTP Server to Transfer Files”

Making the Switch to a Standing Desk

Posted on by rchapin

A few years back I had an office mate who used a standing desk.  He said that he had been using a standing desk for many years and that once he got used to it he liked it much better.  Since then, I have noticed a number of studies that indicate sitting for extended periods of time is just plain bad for you.

For a while I have been wanting to make the switch, and today I took the plunge.→ Continue reading “Making the Switch to a Standing Desk”

Associating Eclipse .launch Files with the Eclipse XML Editor

Posted on by rchapin
  1. Open the Preference dialog and go to General/Editors/File Association.  Add a new file type with the *.launch suffix.  In the ‘Associated Editors’ box below, click on Add and assign the XML editor to the file type.
  2. In the Preferences dialog go to General/Appearance/Content Types.  Click on the + next to Text.  Click on ‘XML’ in the tree so that it is highlighted.  Click ‘Add’ in the box below and add the *.launch suffix
→ Continue reading “Associating Eclipse .launch Files with the Eclipse XML Editor”
© 2005 Ryan Chapin