A Guide To Video And Audio Conversion Using FFmpeg

Table of Contents

• Install ffmpeg
• Convert between different video formats
• Convert video to audio
• Add Text Subtitles to a Video
• Create gif from video
• Mix video and audio
• Extract part of the video
• Contact multiple videos
• Selecting your codecs for conversion
• Reduce the size of the video
• Extract images from video
• Convert images into a video
• Add images to audio
• Option Lists
• More Tips about ffmpeg
• Online Tools

LinkedIn Tips and Tricks

Settings

How to view other people’s LinkedIn profiles anonymously

• Go to Settings & Privacy -> How others see your LinkedIn activity -> Profile viewing options -> Change to Anonymous LinkedIn Member

Changing Active Status

• Go to Settings & Privacy -> How others see your LinkedIn activity -> Manage active status -> change to None

Urls

• Recent activity: /in/the_user_name/detail/recent-activity/shares/
• in/the_user/detail/recent-activity/posts(or shares)

Add People

Sometimes we want to add people, such as managers from same company.

People Also Viewed

• People Also Viewed usually shows other people from same company, we can use it to explore and add similar people.
• But when we reach the limit, Linkedin will blur the name and description, we can’t click to that user’s profile
• We can click the user’s image, inspect the element, and find alt="the_user_name" then google search it.

Search

• engineer manager at the_company hiring
• Explore People Also Viewed
• Check the user’s connection
• in/the_user/detail/recent-activity/

Add a note

• Add a note when we send an invitation, include why you want to add him/her: looking for a job and interested in your team, you experience etc.

The problem: Upgrade to Premium to continue searching

Sometimes when we are looking for new opportunities, we may use Linkedin a lot in a short time. You may reach its limit for free user, and ask us to upgrade to Premium to continue searching.

• Use Google search
  • site:linkedin.com/in engineer manager at the_company

The free trial allows you to send 5 InMail

Articles vs. Posts

• “Start a post” vs “Write an article”

Tools

• Linked Helper: automate work with LinkedIn
  • Add thousands targeted contacts

Java Naming Convention and Best Practices

Table of Contents

• A Good Name: clear and precise
• Package Names
• Names for Classes
• Names for Interfaces
• Name for Annotation Types
• Name for Methods
• Name for Test Methods
• Constant names
• Type variable names
• Variables and Method Parameters
• lambda variable name
• Flags
• Camel case
• Long Names Are Long
• Add readable name
• Misc Tips
• Smell for bad names
• Examples
• Common Typos in Names
• Resources

Linux Commands For Beginners

TL;DR

• Basic Linux commands that we use literally all the time.

alias

alias grep=“grep –color” alias

ps

• print pid: ps -C {program-name} -o pid=
• Show full command: ps -f | less
  • ps detects the size of your terminal window and clips to that.

xargs

• use \0 as the delimiter and -0 to use it
  • printf ‘%s\0’ Hello Hola Bonjour | xargs -0 -I _ echo _ Landon

Search

Sort files by date then grep

• ls -rt *.log | xargs grep -l

# Find which jar contains the class
find . -name "*.jar" | xargs grep Hello.class

List open files

• ls -l /proc/${pid}/fd
  • Use this when lsof is not installed
• lsof -p ${pid}

watch

• watch -n 5 curl -s localhost:8983/show/health
• -d: highlights the changes

curl

• –max-time

pbcopy (take standard input to clipboard) + pbpaste (take data from clipboard to standard output)

pbcopy < file.txt
ps aux | pbcopy
pbpaste > pastetest.txt

diff

diff -x '*.foo' -x '*.bar' -x '*.baz' -rq /destination/dir/1 /destination/dir/2

sed

• sed -n ‘16224,16482p’ filename > newfile

System

Check the age of the system

• rpm -qi basesystem | grep “Install Date”

Misc

• cd $(dirname ${file_full_path})
• tar xfz somefilename.tar.gz
• dirname, basename, realpath
• Copy one file to multiple file names
  • cat 1.ods | tee {jan,feb,mar}-{Rep,graph}.ods >/dev/null
• tail -f **/*.log

Get current working directory of a process

• pwdx
• lsof -p | grep cwd
• readlink -e /proc//cwd ##### [View a range of bash history]
• fl -l ${start} ${end}
• history | sed ‘start,{end}p’

Brace expansion

• mkdir -p {f1, f2}
• for i in {1..3}; do echo $i; done
  • {START..END..INCREMENT}

Command History

!!:n	where n is the 0-based position of the argument you want
!$	last argument from previous command
!^	first argument (after the program/built-in/script) from previous command
!!	previous command (often pronounced “bang bang”)
!n	command number n from history
!pattern	most recent command matching pattern
!!:s/find/replace	last command, substitute find with replace
:p	print the command - !!:p, !!n:p

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