TIL (Things I discover Linux/Programming/Automation)

Linux

xargs -n 1 curl -sL < 2018.txt | grep -Eo "<title>.*</title>" The command to extract links using curl

curl -sL https://news.ycombinator.com/item\?id\=18740939 | grep -Eo 'href="(https|http):[^\"]+"' Command to extract the links from hackernews

grep -aEo "<title>.*</title>" -a option process binary file link to sol use ``` backticks to run a command in bash

• We can use this command to generate a grub configuration file, sudo grub-mkconfig -o /boot/grub/grub.cfg,As, grub-mkconfig scans hardrives for bootable operating systems such as windows,mac or linux distros

• To open workspaces on specific windows when using i3 window mananger use the following assign [class="<use your program name here e.g. - Firefox>"] $workspace<eg. 5> and refresh i3-msg reload

• In order to resize images using command you can use the convert command. convert img.jpg -resize 200x200 img-1.jpg and you can also convert to different extenstions using convert command. convert img.png img.jpg

• To add a printer on linux use CUPS web admin http://localhost:631/

• fuser -k <port_name>/tcp use fuser to kill specific ports on linux

• In order to save a file with root permission using vim you can do :w !sudo tee %

• This commands sudo netstat -plunt |grep post outputs the port on which postgres db is running on

• chmod -x allows you to revert the executable created by chmod +x

• you can use ?* to match the rest of the characters when moving the files

Git

In order to delete a branch on git locally you can use git branch --delete <branchname> and if you want to do it remotely you can do git push --delete <branchname>

To delete git commit history do the following

• git checkout --orphan <branch_name>
• git add -A
• git commit --all -m "a message"
• git branch -D <delete the main branch>
• git branch -m <rename the new branch to main branch>
• git push -f origin <new branch>

Python

jinja line break {% autoescape false %} {{ org.backgroundInfo | replace(‘\n’, ‘<br>’) }} {% endautoescape %}