We often get asked, if there's a simple way to join PDFs from many images under linux. The task is very trivial, if you have 1-2 images, as you can use many of the graphical applications. If you have 10-20 or more, we recommend pdfjoin. It runs under Linux on a command line and allows for a quick images to PDF combine.
We regularly post scripts and script snippets that we have found useful in our day-to-day IT support tasks. Here's a quick way to help determine if the week is odd or even using a bash script. You can replace the echo "even" and "odd" with whatever functions you are looking to perform, such as weekly backups for example. Although not tested, this script should also work on any version of Apple's Mac.
Copy and paste this into a file:
The widely used ifconfig is missing from Centos 7.X version of Linux with minimal install. To get it back, run the following command:
yum install net-tools
The command will then be available as usual.
If you don't want to use ifconfig and are wondering how else you can find the IP address, you can run this command:
Due to some corruption issue during ubuntu (and ubuntu based sytems), this error may come up:
apt: relocation error: /usr/lib/x86_64-linux-gnu/libapt-private.so.0.0: symbol _ZN9pkgSystem9LockInnerEv, version APTPKG_5.0 not defined in file libapt-pkg.so.5.0 with link time reference
There's no clear answer on how to fix this or why it happens, but it corrupts the file libapt-private.so.0.0.0. One way to resolve the issue is to copy the file from another ubuntu 16.04 install. (Or you can download it from here: libapt-private.so.0.0.0 version x64)
If a linux reboot fails by just running the reboot command (sometimes there are run away or hanging processes), you may get the following errors (if you view the logs of systemctl, it will give you a better indication of what is crashing and not letting it reboot):
Failed to start reboot.target: Connection timed out
See system logs and 'systemctl status reboot.target' for details.
A quick way to fix this (short of pulling the plug), is to force reboot using systemctl:
We'll use Ubuntu for this example, but essentially you need an ntfs-3g package, which contains ntfsfix. Under Ubuntu, run the following to install it:
sudo apt-get install ntfs-3g
Then this (where /dev/sdd1 would be your ntfs disk):
Depending on what you are trying to fix, you may want to use options -b and -d.
This comes up many times when you need to add a backup super user to MySQL (or MariaDB). Passwords are lost, forgotten, etc and although MySQL allows for a fairly quick password reset, it is always a good idea to have a backup.
Login as root and run the following query. It will add a new user, called "sysadminuser", with access to localhost (ie: the current machine locally). This new user will be allowed to login using the password: "passwordfortheuser". (Change these as needed):
If you have a non-existing (or unplugged) external drive in /etc/fstab, Linux will not boot until you either press S to skip or M for manual mount. This is a desired behavior, because the operating system does not know what is on that external drive and whether it should ignore the error. If the disk is just used for archiving, the system not booting can be a problem, especially if the disk is just temporarily removed.
To avoid this, you have to add nofail to the fstab, so if the disk becomes detached, the system will continue to boot.
Here's an example:
Linux allows you to access an ISO image, rather than having to burn a CD or DVD. Keep in mind that the image will be read-only.
Assuming your ISO image is in ~/Downloads/ and you have a directory called /media/cdrom (these are usually created automatically during the install)
You can achieve this using the following command.