cloud engineer
How to reinstall the latest kernel and rebuild initramfs.
Find the latest kernel.
rpm -qa kernel
kernel-3.10.0-1160.6.1.el7.x86_64
kernel-3.10.0-1160.11.1.el7.x86_64 |
Remove the kernel first, then reinstall.
yum remove kernel-3.10.0-1160.6.1.el7.x86_64 yum install kernel-3.10.0-1160.6.1.el7.x86_64 |
Removing sudo password is typically not a good practice. If you’re a seasoned system administrator, or you’re the only one using your own desktop, being prompted for a sudo password can get really annoying. Here’s how to stop getting prompted every time you run sudo.
Run visudo.
sudo visudo |
Edit the sudo line and set to below.
%sudo ALL=(ALL) NOPASSWD: ALL |
Save file.
Here’s the command to remove quotes from a string in Bash by using the tr -d command. I’m using jq tool to extract the access key from a json file. Bash returns a string surrounded by quotes. To remove the quotes, just pipe the string to the tr -d command.
jq .AccessKey.AccessKeyId key.json |
Result:
"ASDFSDFSDFASDFSDFSDFGHGDF" |
Using tr -d.
jq .AccessKey.AccessKeyId key.json | tr -d \" |
Result:
ASDFSDFSDFASDFSDFSDFGHGDF |
Snap is cool, but not for everyone. To remove, follow these steps.
# get list snap list # remove snaps. repeat for each app. snap remove chromium # remove snapd apt purge snapd # remove snap from home rm -rf ~/snap # clean up cache rm -rf /var/cache/snapd apt purge snapd |
Here’s the command to stop and remove all Docker containers.
docker stop $(docker ps -a -q) docker rm $(docker ps -a -q) |
How to check which kernel is running on your system
uname -sr |
List all kernels installed on the system.
rpm -q kernel |
Removing old kernels using package-cleanup. This keeps 2 kernels on the system.
yum install yum-utils package-cleanup --oldkernels --count=2 |
I keep forgetting this command. This is to remove tabs from multiple lines in Sublime Text.
Shift+Tab |
How to remove repos in Yum. Just delete the repo file in /etc/yum.repos.d.
rm /etc/yum.repos.d/repo-name.repo |