AWK in Linux

awk Linux Commands

What is Linux awk Command?

Explanation

awk COMMAND:
awk command is used to manipulate the text.This command checks each line of a file, looking for patterns that match those given on the command line.

SYNTAX:
The Syntax is
awk ‘{pattern + action}’ {filenames}

OPTIONS:

-W version Display version information and exit.

-F Print help message and exit.

EXAMPLE:
Lets create a file file1.txt and let it have the following data:

Data in file1.txt
141516
151511
5566
5251

To print the second column data in file1.txt

awk ‘{print $2}’ file1.txt

This command will manipulate and print second column of text file (file1.txt). The output will look like

15155625
To multiply the column-1 and column-2 and redirect the output to file2.txt:

awk ‘{print $1,$2,$1*$2}’ file1.txt > file2.txt

Command Explanation:
$1: Prints 1st column
$2: Prints 2ndcolumn
$1*$2: Prints Result of $1 x $2
file1.txt: input file
symbolfile2.txt: output file

The above command will redirect the output to file2.txt and it will look like,
14 15 21015 15 2255 56 2805 25 125

Enjoy !

Alias-Command in Linux

alias COMMAND:alias command allows you to create a shortcut to a command. As the name indicates, you can set alias/shortcut name for the commands/paths which is too longer to remember.

SYNTAX:The Syntax is 
alias [options] [ AliasName [ =String ] ]

OPTIONS:

-a Removes all alias definitions from the current shell execution environment.
-p Prints the list of aliases in the form alias name=value on standard output.

EXAMPLE:To create a shortcut temporarily:

alias lhost=’cd /var/www/html’

This command will set lhost to cd /var/www/html/.

Now if you type lhost it will take you to the specified folder/directory.

To create a shortcut Permanently:
You can put your aliases into the /home/user/.bashrc file. It is good to add them at the end of the file.

alias home=’cd /var/www/html/hscripts/linux-commands’

Now if you type home it will take you to the specified folder/directory.

To create a shortcut for a command:

alias c=’clear’

This command will set c to clear.
Now if you type c it will clear the screen.

Enjoy !