Friday, May 24, 2019

Unix For VLSI Industry - Part 1


Unix is universal and lot of Industry is using this. But still in our education system, it's not part of curriculum. And that's the reason lot of Students faces issues during Interview or after joining companies. Today, I am going to capture few of the commands, I have used in my career and I wish it will help everyone. From Interview point of view, if you will practice to all these - I am sure you will be at good position.

UNIX Commands

  • Few commands- which are not that important but still good to know
    • date
    • whoami: Who Am I - Tells you your user information.
    • clear
    • ps
    • kill
    • basename / dirname : extract file / directory name from full path
    • touch: change file timestamp
  • Commonly used commands
    • echo : print command
    • env:
    • df
    • head / tail : returns first / last lines of a file
    • more
    • wc : word count on files
  • Must known command :)
    • sort : used to sort files in lexicographic order
    • cat: concatenate files and print
    • ls (it's options)
    • cd
    • mkdir
    • rm
    • cp
    • chmod
    • mv
    • pwd
    • grep (it's options): find regular expressions in files
    • vi
    • awk
    • xterm
    • man
    • find: find files by criteria
    • diff: find differences between files
    • tkdiff
    • which

Redirection and pipes: Apart of this there are few processes which we uses very commonly to handle the output of a particular command.
  • prog redirection file
    • < : redirect stdin
    • > : redirect stdout
    • >> : append stdout
    • >& : redirect stdout and stderr
    • >>& : append stdout and stderr
  • prog1 pipe prog2
    • | : redirect stdout of prog1 to stdin of prog2
    • |& : same, with stdout and stderr

Unix Concepts: Understanding of below concepts are necessary.
  • Relative Path and Absolute Path
  • Alias Concepts
  • Tool Binary concepts : It's similar to exe in windows

VI Editor: Few things in the VI Editor (it's very powerful editor in Unix environment).
  • How to Open a file
  • How to Close a file
  • How to Save file
  • Write-append
  • Set number
  • Set nonumber
  • Search – reverse and forward
  • Search and replace – prefix, suffix
  • Delete character
  • Delete line
  • Delete para
  • Jump to any line number
  • Jump to Last line
  • Figure out total line and name of file


In next article, I will try to show you the use model of few of the important commands. Also, I will try to update this list - If, I can figure out any command I have missed here.

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