Introduction to Linux in HPC/Text display search

Video

Linux Introduction Slides 58 - 64 (7 pages)

Slide Layout

   page 1: 
       grep command and syntax
       important options: -r, -i and -I
   page 2: 
       many commands to display text
       cat
       less
       head and tail
   page 3: 40 sec
       console has three streams
           stdin
           stdout
           stderr
   page 4: 
       stream in computing terms
       similar to streaming video
       input/output stream in console
   page 5: 
       input/output streams can be redirected
           redirect stdout
           redirect stdin
           pipe
   page 6: 
       stream append redirection
       numbered streams: 0 for stdin, 1 for stdout, 2 for stderr
   page 7: 
       use grep to search piped output text

Quiz

1. Which command can be used to append text to filename?

	command > filename
	command >> filename

2. How do I find all files containing specific text on Linux?
HINT: use grep command

Click and submit to see the answer

Info:

no tips in this section

Warning:

no warnings in this section

Exercises in Terminal (slide 65)

1. Create a file using cat (some filename) and write some text in it as below. than use grep to find and display the line number and the line with the word Alan in the file.
        the best way to predict
        the future is to invent it
        –  Alan Kay

Answer:

       $ cat > quote.txt <<"EOF" \ > the best way to predict \ > the future is to invent it
       >  - Alan Kay
       > EOF

      EOF mean end of file. Press enter to get a new line while writing text. With cat > filename you write the file content in the file quote.txt.

      Further use grep as below

       $ grep -in alan quote.txt
       3: - Alan Kay

      grep command option -
           - i to ignore case distinctions, so that characters that differ only in case match each other.
           - n for line number