Łukasz Wieczorek's blog

VIM

2026-04-17T00:00:00+00:00

VIM is my favourite terminal editor. I am writing this post for me to easier to switch to Helix which I will follow up with another post.

Before opening:

which -a vim
brew install vim
vim --version
vim Notes.md
vimtutor

To exit:

:q
:q!
:x
:wq

To navigate:

h j k l # train this with muscles
^ # home
$ # end
gg # document beginning
shift + G # document end

In visual mode:

i # insert
a # append
shift + i # append to the beginning of line
shift + a # append to the end of line
dd # delete line
dw # delete word
y # yank
p # paste
u # undo
ctrl + r # redo
shift + v # visual line

In insert mode:

esc # escape to visual mode

Say no!

2024-12-10T00:00:00+00:00

say-no is here.

I built a simple HTML, CSS, JavaScript website around the idea of saying no to things that destroy us.

You can check the source code here.

brew

2024-11-18T00:00:00+00:00

I use MacOS since 2017 and I like to sometimes grab something from the Linux ecosystem. And there is brew. The most basic commands for it are doctor, info, install, uninstall, and upgrade.

brew doctor
brew info ${package_name}
brew install ${package_name}
brew uninstall ${package_name}
brew upgrade

Recommendations

2024-11-04T00:00:00+00:00

Hello there!

I was revieving some old projects and you could get some knowledge about what I found on the Internet by visiting recommendations.

Somehow I had a missing image in the repository.

You can find the repository here.

Sobituaries

2022-02-01T00:00:00+00:00

Hi again!

In the recent month I worked part time on a project of mine called internally sobituaries.

The site is totally in Polish and the purpose of it is to share obituary notices.

The notices cost 5.00 PLN and are paid with Stripe.

The technologies used are mostly Python, Django, DRF, Javascript, jQuery.

EDIT:

The project is now archived.

I'm very tired but I live

2019-11-30T00:00:00+00:00

Oy!

Where's the Linux kernel start?

2019-08-05T00:00:00+00:00

The Linux kernel start is currently here in the start_kernel function.

LDAP nomenclature

2019-06-25T00:00:00+00:00

Recently I had to setup a local LDAP server.

It took me some time to figure out the naming used in LDAP world.

CN = Common Name
OU = Organizational Unit
DC = Domain Component
DN = Distinguished Name

Keybaze mase

2017-05-11T00:00:00+00:00

READ ME

Random findings

2017-05-04T00:00:00+00:00

Secure GPG key generation using gpg:

gpg2 --gen-key
gpg2 --list-keys
gpg2 -K --keyid-format long --with-colons --with-fingerprint
gpg2 --export -a $ID

Other useful GPG commands;

gpg2 --delete-secret-key $email
gpg2 --delete-key $email
gpg --armor --export $email > "${email}.asc"

Long ssh key generation using ssh-keygen:

ssh-keygen -b 16384

Setting fedora docker directories permission using chcon:

sudo chcon -Rt svirt_sandbox_file_t /var/lib/docker/volumes/
chcon -Rt svirt_sandbox_file_t $volume_dir

Burning Ubuntu to USB using dd:

lsblk -f
umount /dev/sdb1
dd if=ubuntu-16.04.2-desktop-amd64.iso of=/dev/sdb bs=4M status=progress
sync

Ignoring changes for file in git:

git update-index --(no-)assume-unchanged

Removing project containers using docker-compse:

docker-compose down --rmi all --remove-orphans

Rebuilding project containers using docker-compose:

docker-compose up --build

Updating all globally installed gems using gem and cut:

sudo gem update `gem list | cut -d ' ' -f 1`

Upgrading to Fedora 26 using system-upgrade:

dnf upgrade --refresh
dnf install --assumeyes dnf-plugin-system-upgrade
dnf system-upgrade download --refresh --releasever=26
dnf system-upgrade reboot

uWSGI maximum scoket connections

2016-10-12T00:00:00+00:00

Were you ever wondering why are you getting HTTP 502 responses from your uWSGI on high connection count?

Setting net.core.somaxconn might help.

Temporarily:

$ cat /proc/sys/net/core/somaxconn
# echo 4096 > /proc/sys/net/core/somaxconn

Temporarily with sysctl:

# sysctl -w net.core.somaxconn=1024

# echo 'net.core.somaxconn=1024' >> /etc/sysctl.conf

Reload kernel parameters after changes:

# sysctl -p

Change uWSGI settings for vassal:

cat /etc/uwsgi/vassals/vassal.ini
echo 'listen = 1024' >> /etc/uwsgi/vassals/vassal.ini

Restart uwsgi:

service uwsgi restart

Debugging Django code

2016-10-12T00:00:00+00:00

Ever tried debugging Django code in the CLI offered by manage.py shell or shell_plus?

It gets nasty when you need to write more than few lines of code to run something.

Here’s what you can do instead:

import os

import django

os.environ['DJANGO_SETTINGS_MODULE'] = 'project.settings'
django.setup()

def main():
    print 'Hello world!'

if __name__ == '__main__':
    main()

Cleaning up old remote branches in Git

2016-10-12T00:00:00+00:00

This time in fish.

git fetch origin --prune
git fetch --all
for branch in (git branch --remote | egrep -v 'develop|master|\*' | tr -d ' ' | sed 's/origin\///'); git push origin ":$branch"; end

Restoring default directories

2016-09-18T00:00:00+00:00

If you are using GNOME or similar desktop environment you might want sometimes delete default directories if you do not use them. Later on you figure out it would be cool to have them back, but when you create a new directory it does not have the good looking icon on it.

You can fix it with the below two commands which will regenerate the default directories.

rm ~/.config/user-dirs.dirs
xdg-user-dirs-update

Checking file encoding

2016-09-14T00:00:00+00:00

Example

Tired of checking file encodings?

cd $directory
for file in *; echo "$file — "(uchardet $file); end

Packages

uchardet

Warmup

2016-09-11T00:00:00+00:00

Intro

I decided to use this blog as a place were I share things I discover when working as a software engineer.

Starting with shell commands!

I am using Debian and Bash or Fish (you might want to ask which operator has higher precedence here).

Line endings

Ever thought how to convert those ^M characters in VIM that represent Windows line endings (CRLF) to Unix line endings (LF)?

You can do it with tr or dos2unix:

tr -d '\015' < $input > $output

dos2unix $input

If you need to convert all files in a directory use find with exec flag:

find $directory -type f -exec dos2unix {} \;

Finding packages

Now how do I know what package has the dos2unix executable?

dpkg -S $executable

there is also another program which does the same:

dlocate $executable

and another:

apt-file update
apt-file search $executable

Notice that this produces lots of output if you give it just the name, try with full path instead.

whereis $executable
which $executable
apt-file search $full_executable_path

Secure data erasure

You sometimes do not want others to recover your files, say for example, with passwords right?

wipe $file
wpie -r $directory

Git history start rewrite

You work with Git, right? How do you rebase the initial commit then?

git rebase --interactive --root

In-place file modification

You probably tried:

tr 'a' 'z' < $input > $input

somewhere in time and it did not work, leaving you with empty file.

Well you cannot read and write at the same time from and to the same file because it is being processed.

Think of it as changing the for loop index while in the loop.

But you probably just want to do the operation in place, and there is a way.

Ta da, da da dam: SPONGE!

tr 'a' 'z' < $input | sponge $input

Outro

Please, please, please

Please share the post if you liked it.

Thanks!

Appendix

Packages:

coreutils, dos2unix, findutils, dpkg, dlocate, apt-file, debianutils, wipe, git, moreutils.

Credits:

First post with TinyPress!

2016-03-07T00:00:00+00:00

I love simple and minimal design, therefore the decision to use TinyPress as my blogging platform is obvious!