Viewing Text and Redirecting Output

Question 1

What is a file perusal filter for crt viewingq and provides a filter for paging through text one screenful at a time?

Answer 1

More
-use more followed by the file name it will allow you to view and move around the file

Question 2

What is a text viewing utility similar to more but with more features like backward movement?

Answer 2

less

Question 3

What command outputs the first part of files?

Answer 3

head
-the -n option specific the number of lines to print rather then the default of 10
-type head follower by text file for example head /var/log/messages and it will show a default of 10 first lines. To change do head -n /var/log/messages

Question 4

What command outputs the last part of files?

Answer 4

tail
-the -n option specifies the number of lines and -f is used to append data as the file grows (log file)
Example. tail -f /var/log/messages this will show the new messages as they are happening. Good if you are following an active incident or issue to show the logs in a server

Question 5

What command prints lines matching a pattern?

Answer 5

grep
- -i option ignores case
- -R option reads files under each directory recursively
Example use grep then a line of text and then wehre you want to search for that text. So grep hello /var/log/messages it will output every line that has the word hello in /var/log/messages
If you do grep -R cloud_user /var/log/ it will search every directory and file within the log directory

Question 6

What command sorts lines of text files and what order?

Answer 6

sort…ascending alphabetical order
- can be reversed with -r option
- -n used to sort numerically
-can sort multiple files

Question 7

What are the file descriptors?

Answer 7

0: input stdin
1: output stdout
2: stderr

Question 8

Output redirection

Answer 8

> > >

Question 9

Input redirection

Answer 9

< «

Question 10

Error Redirection

Answer 10

2>

Question 11

Redirect stdout and stderror (Merge)

Answer 11

2>&1 and &>

Question 12

What is pipeline redirection

Answer 12

A pipe | allows the output of one command to serve as the input of another command