Posts

---

• Big O notation for many datatypes

  May 20, 2016 · 1 min read

  An interesting site which shows the Big O notation for all many commonly used datatypes is the Big O Cheatsheet.

• Show open ports on the linux shell

  Apr 11, 2016 · 1 min read

  If you want to show all the currently open ports on linux, just use the following command:

  netstat -lntu
  

  This gives you the following output:

  Active Internet connections (only servers)
  Proto Recv-Q Send-Q Local Address           Foreign Address         State
  tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN
  tcp        0      0 0.0.0.0:3128            0.0.0.0:*               LISTEN
  tcp6       0      0 :::22                   :::*                    LISTEN
  udp        0      0 0.0.0.0:39790           0.0.0.0:*
  udp        0      0 0.0.0.0:68              0.0.0.0:*
  udp        0      0 0.0.0.0:41121           0.0.0.0:*
  udp6       0      0 :::57063                :::*
  udp6       0      0 :::42147                :::*
  

  Found here

• Using git efficiently on the console

  Apr 7, 2016 · 1 min read

  I was looking for ways to visualize the progress of a project and also I wanted to do this with on-board tools. After a quick search I found the following command.

  git log --graph --decorate --oneline
  

  This gives a nice and colorful overview when what branch was touched and how it was merged. To display the results in a nicer way, a alias in the ~/.giconfig helps:

  [alias]
  lg = !"git lg1"
  lg1 = !"git lg1-specific --all"
  lg2 = !"git lg2-specific --all"
  lg3 = !"git lg3-specific --all"
  
  lg1-specific = log --graph --abbrev-commit --decorate --format=format:'%C(bold blue)%h%C(reset) - %C(bold green)(%ar)%C(reset) %C(white)%s%C(reset) %C(dim white)- %an%C(reset)%C(bold yellow)%d%C(reset)'
  lg2-specific = log --graph --abbrev-commit --decorate --format=format:'%C(bold blue)%h%C(reset) - %C(bold cyan)%aD%C(reset) %C(bold green)(%ar)%C(reset)%C(bold yellow)%d%C(reset)%n''          %C(white)%s%C(reset) %C(dim white)- %an%C(reset)'
  lg3-specific = log --graph --abbrev-commit --decorate --format=format:'%C(bold blue)%h%
  

  The last speed trick is, to set an alias in the ~/.bashrc. This saves 2/3 of the letters.

  alias g='git'
  

• Combining multiple CSV files to one

  Feb 23, 2016 · 1 min read

  If you have multiple CSV files with the same format and you want to combine them to just a single file, just do

  cat file1.csv file2.csv > output.csv
  

  Or even simpler

  cat *.csv > output.csv
  

• Counting lines of a text file

  Feb 19, 2016 · 1 min read

  To count lines of one or many files on the shell I use wc (Wordcount). If you want to count all lines of all CSV files in a dictionary, just type:

  wc -l *.csv
  

Previous Page: 26 of 28 Next