To modify ip-tables directly in ubuntu
First save off your current config:
$ sudo -s $ iptables-save > /root/working.iptables.rules
$ iptables-save > /root/working.iptables.rules.to.modify
At this point you can modify the file. Once your are satisfied restore it
# iptables-restore < /root/working.iptables.rules.to.modify
Configure postfix with Gmail via Webmin
This assumes the user has webmin installed and understands how to log in and use it. (Usually bring it up in a browser at https://localhost:10000 )
Make sure that postfix is installed. In Webmin this is done by going to “System”, “Software Packages” then clicking on “Package from APT” and . . . → Read More: Configure postfix with Gmail via Webmin
Useful Linux Commands (Red Hat)
(http://www.cse.buffalo.edu/~eisner/DLW) Revised 3/1/2000
Getting information man commandname display the manual page for a particular command named commandname man -S sectionnumber commandname display the manual page under a specific section numbered sectionnumber for the command named commandname. Sometimes the same command will exist in more than one section. man alone will . . . → Read More: Red Hat Linux cheat sheet commands examples RHEL
Add Public SSH Key to Remote Server in a Single Command From HowToGeek
If you want to setup SSH keys to allow logging in without a password, you can do so with a single command.
The first thing you’ll need to do is make sure you’ve run the keygen command to generate the keys:
. . . → Read More: Add Public SSH Key to Remote Server in a Single Command
How to find files, programs, etc using freebsd
The locate command is good for finding files and directories. Enter something similar to:
locate someprogram | more
If that doesn’t work, perhaps try the whereis or find commands:
whereis someprogram | more
find / -name "someprogram*"
For variations on these commands, you can type:
To find the largest ten files on the disk: . . . → Read More: freebsd find
How do you find large files or directories on your disk in freebsd, unix, linux ?
Linux find large files examples; find large files on your disk in *nix.
All *nix systems List total size of each directory/file at current path level
du -sk * | sort -rn | head
[root@centos6 /]# du -sk * | sort -rn | head
Redhat/CentOS Human Readible, List largest 20 files on disk . . . → Read More: Linux find large files
TrueCrypt is by far my favorite hard disk encryption program. It works on Windows, Mac, Linux, etc. and is open source.
Main Features: Creates a virtual encrypted disk within a file and mounts it as a real disk. Encrypts an entire partition or storage device such as USB flash drive or hard drive. Encrypts a partition or drive . . . → Read More: Freeware: TrueCrypt Hard Disk Encryption