How to use File Filter commands in Linux/Unix

File Filter commands in Linux/Unix

Linux flavors come with various powerful file filtering
commands. Filter commands in linux are used to filter the output so that the required
things can easily be picked up. You can get fast results and which O/P you want
just with the help of some simple commands.
Use Different file filter commands in Linux or Unix are as follows:
#wc
#less
#more
#head
#tail
#sort
#sed
 
1) Wc:
 
 The wc
command used to see the no of characters in a file
$wc
– c <file name>
[root@rahul
~]# wc –c file1
The wc command used to see the no of words
in a file
 $wc -w
<file name>
[root@rahul
~]# wc –w file1
The wc command used to see the no of lines
in a file
 $wc -l
<file name>
[root@rahul
~]# wc –l file1
The wc command used to see the no of lines,
words, characters at a time
$wc
<file name>
[root@rahul
~]# wc file1


2)Less
:
 

 

The less command is
used to see the output line wise or page wise
$less  <file name>
[root@rahul
~]# less /etc/passwd
Note
:

press Enter key to scroll down line by line
      Use d to go to the
next page
      Use b to go to
previous page
      Use / to search for
a word in the file
Use v to go vi mode where you can edit the
file and once you save it you will back to less command
      3)  More
:
 
More is exactly same
like less command
$more
<file name>
[root@rahul
~]# more /etc/passwd
Note
:

press Enter key to scroll down line by line
      Use d to go to the
next page
      Use b to go to
previous page
      Use / to search for
a word in the file
Use v to go vi mode where you can edit the
file and once you save it you will back to more command
     4)
Head
:
 
It is used to display
the top 10 lines of the file
$head
<file name>
[root@rahul
~]# head /etc/passwd
To
Display the custom lines:
$head
–n  <file name>

(where n can be any number)
[root@rahul
~]# head -5 /etc/passwd
     5)
Tail
:
 
It is used to display
the last 10 lines of the file
$tail
<file name>
[root@rahul
~]# tail /etc/passwd
        To Display the custom lines:
         $tail –n  <file name>
(where n can be any number)
[root@rahul
~]# tail -5 /etc/passwd
    6)
Sort
:
 
It is used to sort the
output in numeric or alphabetic order
$sort
<file name>
[root@rahul
~]# sort file1
Linux
is opensource
Linux
is opensource
Linux
is opensource
Welcome
to linux
Welcome
to linux
To sort the file according to numbers:
 
$sort
–d <file name> or $sort –h <file name>
 
[root@rahul
~]# sort –h file1
1.Welcome
to linux
2.Linux
is opensource
3.Linux
is opensource
4.Welcome
to linux
5.Linux
is opensource
To remove the duplicate entries from the output
 
$sort
–u <file name>
 
[root@rahul
~]# sort –u file1
Linux
is opensource
Welcome
to linux
     7)
Sed
:
 
Sed stands for stream editor, which is used to search
a word In the file and replace it with the word required to be in the output.
Note: it will only
modify the output, but there will be no change in the original file
$sec
‘s/searchfor/replacewith/g’ <file
name>
 
[root@rahul
~]# sed ‘s/linux/unix/g’ file1
Linux
is opensource
Welcome
to unix
Linux
is opensource

 

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