* whoami : displays current user * top : displays the top cpu/memory eaters and system load.. like task manager on windows * ps : displays all processes running.. ps aux is the most useful way to run it * wall “some text” : sends a broadcast message to all logged on users * man… Continue reading Basic commands
Author: admin
File System
/ : root of the file system contains all devices and directory’s /root : the root users home directory /home : all other users home dirs reside in here /boot : All the kernels and boot specific info /tmp : temporary files are stored here, is commonly world writable so keep an eye on it… Continue reading File System
Basics
I see most of the people searching for basics on linux and found much difficult to get it in short. I have gathered some from a wiki and will add to this section. This might help some of you guys 🙂
How to Disable Telnet access on server
Telnet should be disabled on all web servers, and you should use SSH which is more secure. Telnet sends password in plain text passwords and usernames through logins, and ‘crackers/hackers’ can obtain these passwords easily as compared to SSH. TELNET server listens for incoming messages on port 23, and sends outgoing messages to port 23.… Continue reading How to Disable Telnet access on server
Installing qmHandle
qmHandle is a simple program which allows you to view and manage the qmail queue. Installation: wget http://jaist.dl.sourceforge.net/sourceforge/qmhandle/qmhandle-1.3.2.tar.gz tar xvzf qmhandle-1.2.0.tar.gz chmod 777 qmHandle ./qmHandle –h That will show you how to use ./qmHandle Now, i am writing few tips how to use it. /root/qmHandle/ -s Messages in local queue: 0 Messages in remote queue:… Continue reading Installing qmHandle
OpenSSL Tricks
Create a strong CSR and private keyopenssl req -new -nodes -newkey rsa:2048 -out server.crt -keyout server.key Parsing out the data within a certificateopenssl asn1parse -in server.crt Checking a certificate/key modulus to see if they correspondopenssl rsa -in server.key -modulus -noout | openssl md5openssl x509 -in server.crt -modulus -noout | openssl md5 Convert a key… Continue reading OpenSSL Tricks
Rebuilding the initial ram disk (initrd)
Installing new hardware may mean that new kernel need to be loaded when your server boots up. There’s a two step process to making a new initrd file: First, add the appropriate line to your /etc/modules.conf or /etc/modprobe.conf which corresponds to your new kernel module. Next, rebuild the initial ram disk after making a… Continue reading Rebuilding the initial ram disk (initrd)
Register to Red Hat Network
rhn_register that will register your server over at RHN. Well if you want to upgrade your kernel… you’ll have to edit the config to NOT skip the kernel up2date –configuretype 24and then type C and hit enterand then hit enter again Type:up2date -pthat will update the packages your server to reflect the packages available… Continue reading Register to Red Hat Network
Adding IP aliases in FreeBSD
One question I hear quite often is “how do I add IP aliases in FreeBSD?” It’s not terribly intuitive, but you can follow these steps: Example:Server’s primary IP: 192.168.1.11 Additional IP’s to add: 192.168.1.12, 192.168.1.13, and 192.168.1.14 Boot-time configuration:Add it to /etc/rc.conf first (so you don’t forget). In this example, we have a Realtek… Continue reading Adding IP aliases in FreeBSD
Hello world!
My first post 😉