Difference between revisions of "Introduction to Linux in HPC/Text display search"

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m (Fixed the answer 4 to question no. 2, so that at least one answer is correct.)
 
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- <code>command | filename</code>
 
- <code>command | filename</code>
 
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+ <code>command 2>$1 > filename</code>
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+ <code>command > filename 2>&1</code>
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|| Explanation: The <code>2>$1</code> operator redirects the error of command into filename which is given after the command <code>></code>. If filename exists already, its contents will be overwritten.
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|| Explanation: The first <code>></code> operator redirects the standard output of command into filename. The second <code>></code> operator redirects the standard error (2) of command into the file descriptor <code>(&)</code> of standard output (1), which in this case is the same as filename. If filename exists already, its contents will be overwritten.
 
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=== Exercises in Terminal (slide 65) === <!--T:5-->   
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=== Exercises in Terminal === <!--T:5-->   
  
 
  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.
 
  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.

Latest revision as of 09:41, 11 December 2020

Tutorial
Title: Introduction to Linux in HPC
Provider: HPC.NRW

Contact: tutorials@hpc.nrw
Type: Multi-part video
Topic Area: HPC Platforms
License: CC-BY-SA
Syllabus

1. Background and History
2. The Command Line
3. Linux Directory Structure
4. Files
5. Text display and search
6. Users and permissions
7. Processes
8. The vim text editor
9. Shell scripting
10. Environment variables
11. System configuration
12. SSH Connections
13. SSH: Graphics and File Transfer
14. Various tips

This part of the tutorial introduces the text input and output of the Linux console as well as common text based operations. It explains how different types of in- and output can be handled as well as different ways of text based console commands, their usage and their differences.

Video

( Slides as pdf)

Quiz

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

command > filename
command >> filename

2. Which is the correct way to redirect stdout and stderr to the same file?

command > filename
command 2> filename
command | filename
command > filename 2>&1

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

Click and submit to see the answer

Exercises in Terminal

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


<< Files

Overview

Users and Permissions >>

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