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Filter Commands in Unix | Cut Command with Examples

Cut Command with Examples :

In Previous articles i have given the overview of most commonly used unix commands,Working with unix directories. In this article i will explain some important Filter Commands in unix with real life examples.Filter commands are basically used to filter the words,files,lines in the files e.t.c. In this article i will try to explain Simple filter commands with real life examples like cut command with examples .You will find following commands with examples in this article:

1.Cut

2.Paste

3.tr

4.Banner

Flat files in unix :

Before starting with the commands first we need to understand what exactly the flat files in unix. We will use the same flat files in our examples.The file is said to be a flat file If,

a) In a file data entered by using delimiter is known as flat file

b) The default delimiter is Tab key

c) Delimiter means field separator(it Should be ,(Comma);Pipe |,Space)

d) Enter key means record separator

Real Life Example:

Create a Student flat file with Student_Id, Name, Ph_Nos, Course and Loc with default delimiter (Tab Key).

$ cat>Student

101 Amit 9988554411 Unix Pune

102 Rahul 8899774444 Oracle Mumbai

103 Deepu 88777444444 dba Hydrabad

104 Ram 9868536451 perl UK

105 Sonali 9868587458 unix US

106 Reshma 7788444444 oracle Algeria

107 Kishore 9868597851 dwh Hydrabad

Ctrl+d

Creating Flat File using Comma Delimiter :

Create Emp flat file with EmpNo, Ename, Sal and DeptNo with comma delimiter.

$cat>Emp

101,Sonali,50000,10

102,Pradnya,60000,20

103,Amit,80000,10

104,Rohit,65000,30

105,Ankit,50000,20

Ctrl+d

1.Cut Command with Examples :

Cut command is filter command which is used to fetch sections of the specified file.Cut command is used to extract specific fields and characters from the given file.You can be able to select the fields or columns from the line specifying the delimiter.

Real life Examples:

Creation of file :

$cat>Employee.txt

Amit,10000,10

Pradnya 2000,5

1.1.Cut Command to fetch character by position :

Syntax :

$Cut -c Position Filename

Example :

$Cut -c 3 Employee.txt

The above command will display 3rd character of Employee.txt

Output:

i

a

1.2.Cut Command to fetch character by Range:

Syntax :

Using -C option :

$Cut -c Range(- Operator used) Filename

Using -F Option :

$Cut -f Range(- Operator used) Filename

Example :

$Cut -c 1-3 Employee.txt

$Cut -f 1-3 Employee.txt

The above command fetches the text which has range 1 to 3.

Output :

Ami

Pra

1.3.Cut Command to fetch separate character in given Range:

Syntax :

Using -C option :

$Cut -c Range(, Operator used) Filename

Using -F Option :

$Cut -f Range(, Operator used) Filename

Example :

$Cut -c 1,3 Employee.txt

$Cut -f 1,3 Employee.txt

The above command fetches the chaaracters which has position 1 and postion 3.

Output :

Ai

Pa

1.4.Cut Command to fetch separate character in given Range using Delimiter:

Syntax :

Using -C option :

$Cut -c Range(Delimiter) Filename

Using -F Option :

$Cut -f Range(Delimiter) Filename

Example :

$Cut -c 1,3 ‘,’Employee.txt

$Cut -f 1,3 ‘,’ Employee.txt

The above command fetches the chaaracters which has position 1 and postion 3 which has comma Delimiter.

Output :

A,i

P,a

1.5.Cut Command used to display first field in etc/passwd file command :

The passwd file is delimeter file which is seperated by colon (:) delimitor. The Cut command is used to display the first field of passwd file.

Example :

$Cut -d ‘:’ -f etc/passwd

Output :

@

It dispays first character of the passwd file which is ‘@’.

2.Paste Command with Examples :

Paste command is one of the useful and most used linux or unix command which is used to merge the characters or lines of 2 different files.Paste command sequencially writes the corresponding lines from each specified file,

Syntax :

Paste Options File1..File2…File n

Following are important options of Paste Command

-d -Specify the list of file delimiters
-s- Paste one file at a time instead of parallel
–help – You will get help for paste command using the above option.

Create following 2 files for Example :

$cat>States

MH

AP

Ctrl+d

$cat>Cities

Pune

Hydrabad

Ctrl+d

2.1.Merge Files parallel :

Syntax:

Paste File1 File2..FileN

Example:

$ paste States Cities

The above paste statement Merges 2 files in following fashion.By Default it has taken tab (Space) as delimiter

Output :

MH Pune

AP Hydrabad

2.2.Merge Files parallel Specifying the Delimiter:

Syntax:

Paste -d “Delimeter” File1 File2..FileN

Example:

$ paste -d ‘,’ States Cities

The Above statement takes comma as delimeter and merges two files.

Output :

MH,Pune

AP,Hydrabad

2.3.Merge Files Sequencially :

Syntax:

Paste -s File1 File2..FileN

Example:

$ paste -s States Cities

Above statement merges 2 Files sequencially named States and Cities.

Output :

MH AP

Pune Hydrabad

2.4.Merge Files Sequencially using Delimeter:

Syntax:

Paste -s -d [Delimeter] File1 File2..FileN

Example:

$ paste -s -d ‘,’ States Cities

Above statement merges 2 Files sequencially named States and Cities.

Output :

MH,AP

Pune,Hydrabad

3.Translate Command (tr) in unix :

Tr command is also mostly used unix Filter Commands which stands for translate and used to translate file character by character.

Syntax :

Tr[Options] Data set1..Data set2…Data set N

Options of Translate command :

-d -Which deletes the Characters in data set 1.
-c -complements the set of characters in specified string
-t : Which is used to truncate data set 1
-s : Replaces the repeated characters listed in set 1 with single occurance.

3.1. Converts Lowercase letters to uppercase letters and uppercase letters to lowercase letters (method 1):

Tr command used to translate the lowercase letters in to uppercase letters.

Create file :

$ cat>Linux.txt

I am learning unix

Ctrl+d

Syntax for lowercase to uppercase :

tr “[:lower:]” “[:upper:]” < File_name

Syntax for uppercase to lowercase :

tr “[:upper:]” “[:lower:]” < File_name

Example :

tr “[:lower:]” “[:upper:]” < Linux.txt

Output :

I AM LEARNING UNIX

tr “[:upper:]” “[:lower:]” < Linux.txt

i am learning unix

3.2. Converts Lowercase letters to uppercase letters and uppercase letters to lowercase letters (Method 2):

Syntax for lowercase to uppercase :

tr “[a-z]” “[A-Z]” < File_name

Syntax for uppercase to lowercase :

tr “[A-Z]” “[a-z]” < File_name

Example :

tr “[a-z]” “[A-Z]” < Linux.txt

Output :

I AM LEARNING UNIX

tr “[A-Z]” “[a-z]” <Linux.txt

i am learning unix

3.3 Replacing the Delimeter :

Tr command is also used to replace the delimeter in the file.

Syntax :

tr ‘ Delimiter used in file’ ‘Delimeter you want to use’ < File_name

Example :

tr ‘\t’ ‘,’ < Linux.txt

It replaces tab with comma.

Output :

I, am,Learning,Unix

3.4. Replacing non matching characters :

tr command is used to replace non-matching characters.

Example :

$echo “Amit” | tr -c “A” “P”

Output:

APPP

tr has replaced each and every character except character ‘A’ with P.

3.5.Delete Specific character from the File:

Example :

$tr -d ‘U’ <Linux.txt

Output:

I am learning nix

The character ‘U’ has been deleted.

3.6. Use of “aeiou” vowels :

With tr command you can use “aeiou” vowels to delete or convert it to uppercase and lowercase letters.

Examples :

$ tr “aeiou” “AEIOU” <Linux.txt

It replaces Lower Case characters with Upper Case by considering vowels.

Output :

I Am lEArnIng UnIx

Example 2 :

$ tr -d “aeiou” “AEIOU” <Linux.txt

It deletes Lower Case “aeiou” characters from Sample file.

Output :

I m lrnng nx

4. Banner Command :

Banner: Banner command prints a message in large letters which look like banner.

$ banner Hello

Note:Banner can accommodate only 10 characters in one line.

I hope you like this article on Cut Command with Examples and other filter commands as well.

Click on Topic You want to learn:

Unix Tutorials :

1.What is unix?

2.Basic unix commands

3.File Commands in unix

4.Create File in Unix using multiple ways

12.paste Command

Hope you will get proper idea about 3 important Filter Commands in unix from this article.If you like this article dont forget to comment in comment section.

Amit S

Oracle Consultant with vast experience in Oracle BI and PL/SQL Development. Amiet is the admin head of this website who contributes by preparing tutorials and articles related to database technologies. He is responsible to manage the content and front-end of the website.