vi is very handy when doing a lot of config file editing and can save you time over using the mouse or using the x or delete keys to manually delete.
Just type "dw" in non-input mode.
Say you have a config file like this:
address-range low 10.10.2.1 high 10.10.2.5;
Let's say you wanted to just remove the whole line, yes you could hit dd but what if you just want everything after ad........
Just a quick note and warning is that if you are testing to see if EFIPXE booting works on a VM, MAKE SURE it actually works. For example Iinitially tested using my Distro's QEMU 2.5+dfsg-5ubuntu10.46 and ovmf BIOS firmware (OVMF supports EFI). However, I found on old versions of QEMU (like 2.5), EFIbooting with GRUB NEVER works so it may appear that you have made a mistake when everything is fine when you boot a physi........
Traditionally kernels were numbered starting from 0 but by default the "new style" of grub boot loading considers each subkernel item to be different so if you have 3 entries for 4.40-148 rather than counting for 1.
To get the expected behavior let's show this example and how we can boot it
We do a grep on menuentry in /boot/grub/grub.cfg to see all of the bootable kernels rather than scrolling through loads of extra entries we don't care about (thou........
Most newer distros inexplicably cause your NIC to have what Icall "random" non-standard name conventions because of systemd.
This is a big problem for many people and especially those running servers. Imagine that you have a static IPconfigured for ens33 but then the hard disk is moved to a newer system, the NIC could be anything from ens33 to enp0s1, meaning that manual intervention is required to go and update the NIC config file (eg. /etc/network/interfa........
This is a security hole in my opinion and should be plugged by editing the lock screen ui layout:
#find these objects and set the visible property to false
object class="GtkLabel" id="note-tab-label"
object class="GtkLabel" id="auth-username-label>
object class="GtkLabel" id="auth-realname-label"........
#mount the VCSA DVD
mount /dev/sr0 /mnt/cd
#alternatively you could mount the iso directly
mount -o loop vcsa.iso /your/mount/path
#for this purpose we are using the CLI installer on Linux
#no it's not going to be that easy you can't just run vcsa-deploy like that you need to use a template or configured .json file
Usage: vcsa-deploy [-h] [--version] [--supported-deploymen........
This is most likely to happen on a normal GUI system like Ubuntu or Linux Mint. If you or the user is meant to have sudo / root privileges it is as simple as editing the following files:
Now assume your username is "iamtheuser"
Find the above lines and add a comma and "ia........
In Centos 7 the days of editing the "kernel"line and adding "single"are gone. On top of that sometimes after a new install passwords do not work, maybe you forgot your password or for some other reason you need to break in or fix your system? It could also be because you can't mount your root / or some other /etc/fstab error and many other errors.
1. Edit your grub settings and find the linux16 /vmlinu........
Here is the scenario you or a client have a remote machine that was installed as a standard/default minimal Centos 6.x machine on a single disk with LVM for whatever reason. Often many people do not know how to install it to a RAID array so it is common to have this problem and why reinstall if you don't need to? In some cases on a remote system you can't easily reinstall without physical or KVM access.
So in this case you add a second physical or disk or already ha........
The most common solution is to use the /etc/postfix/header_checks but this is a big problem.
Why is header_checks a problem? Because it does it to all mail whether incoming or outgoing and whether authenticated or not. We of course want as much header information for incoming as we can get for many reasons but many organizations want to secure and make their mail clients as secure as possible.
I adapted this solution to the client's custom config, they are configur........
I've only ever seen this in Ubuntu for some reason and it is because of the /etc/nsswitch.conf settings.
So the issue is that if the hostname's reverse DNS cannot be found that you need to go back to DNS which was not the default in this nsswitch.conf file for some strange reason.
Edit /etc/nsswitch.conf and replace your "hosts" line with this:
#hosts: files dns mdns4_minimal [NOTFOUND=return] mdns........
#count=10000 makes an image of 10000MB make sure your image is at least the same as your existing
dd if=/dev/zero of=yourimage.img bs=1M count=10000
# losetup -fv newimage.raw
# fdisk -cu /dev/loop0
# kpartx -a /dev/loop0
# dd if= of=/dev/mapper/loop0p1
# e2fsck -f /dev/mapper/loop0p1
# resize2fs /dev/mapper/loop0p1
# a lot of guides tell you to edit /etc/fst........
cat | grub --device-map=/dev/null
Now pay close to the attention of the beginning.
Type: "device (hd0) VPS.img" this is telling what hd0 will be to GRUB and we're telling it the disk image file "VPS.img" in the current directory is hd0, you can specify alternate paths and image names of course.
GNU GRUB version 0.97 (640K lower / 3072K upper memory)
[ Minimal BASH-li........
ERROR 1045 (28000): Access denied for user 'contentmanager'@'localhost' (using password: YES)
For fun I thought I'd reset the password:
GRANT ALL ON thecontent.* TO contentmanager IDENTIFIED by 'dfdfsdfdsfsdfsd';
ERROR 1470 (HY000): String 'contentmanager' is too long for user name (should be no longer than 16)
This is ridiculous that this new version has some bizarre 16 character username limit and not only that but i........
iptables v1.3.5: can't initialize iptables table `nat': Table does not exist (do you need to insmod?)
This solution applies to all other iptables modules/problems for OpenVZ, you'll just need to add them to both lists/lines below if you have modules other than what I have below.
The modules need to be enabled in both iptables and the OpenVZ hostnode itself and then the containers which need it must be restarted.
How To Enable IPTables Modules in OpenVZ........
This is very annoying, the only known fix is to install vim
apt-get install vim
After that everything works as normal.........
Within vi if you can't exit /etc/vim/vimrc you can type
And to turn it back on:
Many of us have a dark/black background in our terminal/shell making the default syntax unreadable, the solution is to either turn off syntax highlighting with :syntax off or to enable a special option in /etc/vim/vimrc
The "syntax on" enables the highligh........
GNU GRUB version 0.97 (640K lower / 3072K upper memory)
[ Minimal BASH-like line editing is supported. For the first word, TAB
lists possible command completions. Anywhere else TAB lists the possible
completions of a device/filename.]
grub> root (hd1,0)
Filesystem type is ext2fs, partition type 0xfd
*remember to apply changes you need to run "newaliases" after editing /etc/aliases
one thing I don't get is that it doesn't allow you to specify the whole e-mail address on the left-hand side
postalias: warning: /etc/aliases, line 109: name must be local (if you try the above)
It works more like this:
Virtualmin Postfix Error:
The status of your system is being checked to ensure that all enabled features are available, that the mail server is properly configured, and that quotas are active ..
A problem was found with your Postfix virtual maps : No map sources were found in the Postfix configuration
.. your system is not ready for use by Virtualmin.
Mencoder is great, you can throw anything at it, including video files from your camera and have it encode into xvid or almost any other format.
In my case I took 640x480 video from my Canon and reduced the size by 1/3 with the options below (there are many other options that you can read about in the manual but I like to keep it simple).
mencoder -ovc xvid -oac mp3lame -xvidencopts fixed_quant=4 -o ........
The New Chips on the BlockThe New Chips on the Block
By Bruce Gain
Story location: http://www.wired.com/news/infostructure/0,1377,67795,00.html
02:00 AM Jun. 13, 2005 PT
We have embarked upon a new era in x86 PC computing -- so say chip giants AMD and Intel following their launches of dual-core PC processors. So how will dual-core processing change your PC computing experience? Our FAQ should help you decide whether or when you sho........
CVSUp the Easy WayIf you're reading this you probably have never used CVSUp or don't know how.
CVSUp can be used for two things or just one if you prefer.
*Keeping your kernel up to date
*Keeping your port list up to date
Start by editing the following file in:
It can be quite overwhelming with all the crazy options.
Basically there are only 3........
You can see the problem below, GRUB recognizes my hard drive and sees the partitions but cannot access them. This is from the GRUB boot disc I'm using.
What happened is that I had some power issues causing this system's power to be interrupted several times and basically an on/off on/off situation.
The system won't boot, I just get a flashing cursor and no message or error from GRUB. Obviously the problem is that my MBR seems corrupt or some other issue.
User username from 127.0.0.1 not allowed because not listed in AllowUsers
What's going on? The user was created properly, it has been defined as having a shell entry and the entry for /etc/passwd and /etc/shadow is set just fine.
This is a new and very smart/secure feature of SSHD. It is simple and yet effective, but also very annoying if you didn't know about it being implemented and that hand editing of /etc/ssh/sshd_config is required to allow a newly add........