FILTER Commands

1. Simple Filters: more,less,head,tail,cut,sort,paste,tr,wc,comm,unique and join
2. Advanced Filters: pipe,grep,sed and awk

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FMT

Desc ------>> fmt command is useful to display in single line multiple words into individual records separated by space.

[haritaraka12078@cxln4 ~]$ cat>site.txt

sunday monday tuesday wednesday thursday friday saturday

[haritaraka12078@cxln4 ~]$ fmt -w 1 site.txt

sunday

monday

tuesday

wednesday

thursday

friday

saturday

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CAT

[haritaraka12078@cxln4 ~]$ cat>marks.txt

prabhu-50

hario-40

taraka-60

apple is red

mango is yellow

your dress colour is red

bloack colur suties you perfectly

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Using Hyphen (-) As Delimiter ----------> cut -d- -f(columnNumber) <fileName>

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[haritaraka12078@cxln4 ~]$ cut -d- -f2 marks.txt

[haritaraka12078@cxln4 ~]$ cut -d- -f1 marks.txt

prabhu

hario

taraka

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Using Space As Delimiter ----------> cut -d ' ' -f(columnNumber) <fileName>

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[haritaraka12078@cxln4 ~]$ cut -d ' ' -f2 marks.txt

prabhu-50

hario-40

taraka-60

dress

colur

[haritaraka12078@cxln4 ~]$ cut -d ' ' -f5 marks.txt

prabhu-50

hario-40

taraka-60

red

perfectly

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Cut by Byte ------>> cut -b <byte number> <file name>

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[haritaraka12078@cxln4 ~]$ cut -b 2 marks.txt

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Cut by charecter ------>> cut -c < characters> <file name>

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[haritaraka12078@cxln4 ~]$ cut -c 1,6 marks.txt

[haritaraka12078@cxln4 ~]$ cut -c 1-6 marks.txt

prabhu

hario-

taraka

apple

mango

your d

bloack

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Cut by Complement Pattern--->> cut --complement < complement pattern> <file name>

---------------------------------------------------------------------------------------

[haritaraka12078@cxln4 ~]$ cut --complement -c 1 marks.txt

rabhu-50

ario-40

araka-60

pple is red

ango is yellow

our dress colour is red

loack colur suties you perfectly

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COMM

COMM ----> 'comm' will always display three columns.

First column indicates non-matching items of first file,
second column indicates non-matching items of second file,
third column indicates matching items of both the files.

Both the files has to be in sorted order for 'comm' command to be executed.

[haritaraka12078@cxln4 ~]$ cat>file1.txt

dhoni

dravid

sachin

sehwag

yuvi

[haritaraka12078@cxln4 ~]$ cat>file2.txt

dhoni

dravid

sachin

zadeja

[haritaraka12078@cxln4 ~]$ comm file1.txt file2.txt

dhoni

dravid

sachin

sehwag

yuvi

zadeja

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To Display Single Column

-------------------------------------------------

If you want to output a single column, you have to specify number of the columns which are not to be displayed.

Syntax:

comm -23 (To display first column)
comm -13 (To display second column)
comm -12 (To display third column)

[haritaraka12078@cxln4 ~]$ comm -23 file1.txt file2.txt

sehwag

yuvi

[haritaraka12078@cxln4 ~]$ comm -13 file1.txt file2.txt

zadeja

[haritaraka12078@cxln4 ~]$ comm -12 file1.txt file2.txt

dhoni

dravid

sachin

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GREP

GREP - "global regular expression print".generally used with pipe (|).
command | grep <searchWord>
Grep with Pipe ->> command | grep <searchWord>

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Grep with PIPE

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[haritaraka12078@cxln4 ~]$ cat marks.txt | grep 6
taraka-60
sunny-60

[haritaraka12078@cxln4 ~]$ cat marks.txt
prabhu-50
hario-40
taraka-60
apple is red
mango is yellow
your dress colour is red
bloack colur suties you perfectly
sunny-60
mhtp-50

------------------------------------------------------------------------
grep without pipe -> grep <searchWord> <file name>

------------------------------------------------------------------------
[haritaraka12078@cxln4 ~]$ grep 6 marks.txt
taraka-60
sunny-60

[haritaraka12078@cxln4 ~]$ grep -v 6 marks.txt
prabhu-50
hario-40
apple is red
mango is yellow
your dress colour is red
bloack colur suties you perfectly
mhtp-50

[haritaraka12078@cxln4 ~]$ grep -i red marks.txt
apple is red
your dress colour is red

GREP Options

grep -A command is used to display the line after the result.
grep -B command is used to display the line before the result.
grep -C command is used to display the line after and line before the result.

[haritaraka12078@cxln4 ~]$ grep -A1 yellow marks.txt
mango is yellow
your dress colour is red

[haritaraka12078@cxln4 ~]$ grep -B1 yellow marks.txt
apple is red
mango is yellow

[haritaraka12078@cxln4 ~]$ grep -C1 yellow marks.txt
apple is red
mango is yellow
your dress colour is red

DESC:

command "grep -A1 yellow marks.txt" displays searched line with next succeeding line,
command "grep -B1 yellow marks.txt" displays searched line with one preceding line and
command "grep -C1 yellow marks.txt" displays searched line with one preceding and succeeding line.

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SED

SED ---->

Linux 'sed' command stands for stream editor.
It is used to edit streams (files) using regular expressions.
But this editing is not permanent.
It remains only in display, but in actual, file content remains the same.

sed [OPTION]... {script-only-if-no-other-script} [input-file]...

SED options------>

-n: ignore duplicates

-e: search for multiple expressions and print

p -print

s- substitute

d- delete

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Applying to the STDIN directory

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[haritaraka12078@cxln4 ~]$ echo class7 | sed 's/class/jtp/'

jtp7

[haritaraka12078@cxln4 ~]$ echo class7 | sed 's/7/10/'

class10

[haritaraka12078@cxln4 ~]$ cat marks.txt | sed 's/prabhu/haritarakaprabhu/'

haritarakaprabhu-50

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Global Replacement ------> command | sed 's/<oldWord>/<newWord>/g'

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[haritaraka12078@cxln4 ~]$ echo class7 class9 | sed 's/class/jtp/g'

jtp7 jtp9

[haritaraka12078@cxln4 ~]$ cat marks.txt | sed 's/red/redddddddddddd/g'

taraka-60

apple is redddddddddddd

mango is yellow

your dress colour is redddddddddddd

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Removing a Line--> cat <fileName> | sed '/<Word>/d'

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[haritaraka12078@cxln4 ~]$ cat file1.txt

dhoni

dravid

sachin

sehwag

yuvi

[haritaraka12078@cxln4 ~]$ cat file1.txt | sed '/dhoni/d'

dravid

sachin

sehwag

yuvi

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Using the Multiple sed Command--------->>sed -e '<script 1> ; <script 2>' <file name>

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[haritaraka12078@cxln4 ~]$ cat marks.txt

prabhu-50

hario-40

taraka-60

apple is red

mango is yellow

your dress colour is red

bloack colur suties you perfectly

sunny-60

mhtp-50

[haritaraka12078@cxln4 ~]$ sed -e 's/red/blue/; s/yellow/black/' marks.txt

prabhu-50

hario-40

taraka-60

apple is blue

mango is black

your dress colour is blue

bloack colur suties you perfectly

sunny-60

mhtp-50

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Reading Commands From a File--------->>sed -f <sed file> <file name>

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[haritaraka12078@cxln4 ~]$ cat>exm.txt

apple is red

mango is yellow

your dress color is red

black color suits you all

[haritaraka12078@cxln4 ~]$ cat>sedcommand

s/red/blue/;

s/yellow/black/;

[haritaraka12078@cxln4 ~]$ sed -f sedcommand exm.txt

apple is blue

mango is black

your dress color is blue

black color suits you all

[haritaraka12078@cxln4 ~]$ sed -n '1p' exm.txt

apple is red

[haritaraka12078@cxln4 ~]$ sed -n '1,3p' exm.txt

apple is red

mango is yellow

your dress color is red

[haritaraka12078@cxln4 ~]$ sed -ne '3p' -ne '4p' exm.txt

your dress color is red

black color suits you all

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Limiting the sed->>

A range of lines.
A pattern that matches a specific line.

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[haritaraka12078@cxln4 ~]$ sed '3s/red/Blue/' exm.txt

apple is red

mango is yellow

your dress color is Blue

black color suits you all

Desc: --------------->. only the line three is modified.

[haritaraka12078@cxln4 ~]$ sed '1,3s/red/Blue/' exm.txt

apple is Blue

mango is yellow

your dress color is Blue

black color suits you all

Desc: ------------>>will update the specified text in lines 1 and 3.

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Inserting and Appending Text---------------------------->>>>

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[haritaraka12078@cxln4 ~]$ echo "Another Demo" | sed 'i\First Demo'

First Demo

Another Demo

[haritaraka12078@cxln4 ~]$ echo "Another Demo" | sed 'a\First Demo'

Another Demo

First Demo

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Modifying Lines-------------->>

-----------------------------------------------------------------------------------------------

[haritaraka12078@cxln4 ~]$ cat exm.txt

apple is red

mango is yellow

your dress color is red

black color suits you all

[haritaraka12078@cxln4 ~]$ sed '3c\This is a modified line.' exm.txt

apple is red

mango is yellow

This is a modified line.

black color suits you all

[haritaraka12078@cxln4 ~]$ sed '/apple is /c Line updated.' exm.txt

Line updated.

mango is yellow

your dress color is red

black color suits you all

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Transformation of Characters----------->>>

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[haritaraka12078@cxln4 ~]$ sed 'y/abc/def/' exm.txt

dpple is red

mdngo is yellow

your dress folor is red

eldfk folor suits you dll

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Printing the Line Numbers--------->>

-----------------------------------------------------------------------------------------------

[haritaraka12078@cxln4 ~]$ sed '=' exm.txt

apple is red

mango is yellow

your dress color is red

black color suits you all

[haritaraka12078@cxln4 ~]$ sed -n '/mango/=' exm.txt -

Desc: ------------->> display the line number that contains the word 'mango'

sed -n '1p' sedfile( To get only first record)
sed -n '1,3p' sedfile(To get first to third record)
sed -ne '3p' -ne '5p' sample.txt(To get first, third record)

substitute
--------------

sed 's/abc/hello/p' sedfile
sed -ne s/abc/hello/p sedfile
sed -ne s/abc/hello/p -e s/venkat/lohith/p sedfile
sed '1wfile_name' sedfile(To write the first record into the file "file_name")
sed '1,4w file_name' sedile
(To write the first 4 records into the file_name file)
sed '3i 500:dfdfdfd:10000' sample.txt (To insert the record after 2nd and before 3rd record)
sed '3a 500:dfdfdfd:10000' sample.txt(To insert the record after 3nd and before 4rd record)
ls -ltr $path |awk -F " " '{print $9}' |sed '/^$/d'>scriptfile.txt ( To delete any blank records)

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TEE Command

Linux tee command is quite similar to the 'cat' command, with only one difference. It puts stdin on stdout and also put them into a file.

Options:

-a, --append: It is used to append the data to the given files, it does not overwrite data.
-i, --ignore-interrupts: It is used to ignore the interrupt signals.
-p: It is used to diagnose errors writing to non-pipes.
--output-error[=MODE]: It is used to set behavior on write error mode.
--help: It is used to display the help documentation.
--version: it is used to display the version information.

Syntax:

tee <options> <file name>

[haritaraka12078@cxln4 ~]$ cat>weeks.txt

sunday

monday

tuesday

wednesday

thursday

friday

saturday

[haritaraka12078@cxln4 ~]$ cat weeks.txt | tee file1.txt

sunday

monday

tuesday

wednesday

thursday

friday

saturday

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Write a file and append output

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The '-a' option is used with the tee command to append the output and write it to a file. Consider the below command:

[haritaraka12078@cxln4 ~]$ echo 'Saturday and Sunday are week offs' | tee -a file1.txt

Saturday and Sunday are week offs

[haritaraka12078@cxln4 ~]$ cat file1.txt

sunday

monday

tuesday

wednesday

thursday

friday

saturday

Saturday and Sunday are week offs

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Write the State of Data to a File

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Writing the state of data is very useful for taking backup or creating a snap of the data for the debugging purpose.
It can be easily done by using the tee comman.

ls ~/ | tee pipe1.txt | grep ^b | tee pipe2.txt | sort -r

[haritaraka12078@cxln4 ~]$ ls ~/ | tee file1.txt | grep ^b | tee weeks.txt | sort -r

[haritaraka12078@cxln4 ~]$ cat file1.txt

abc3

cloudxlab_jupyter_notebooks

dir1

erro-log

exm.txt

file1.txt

file2.txt

hari_dir

hari_training

marks.txt

sedcommand

site.txt

tee4

users-info

weeks.txt

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Write to multiple files

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To write to the multiple files, specify the names of the files after the tee command as follows:
echo " add text" | tee file1.txt file2.txt file3.txt

[haritaraka12078@cxln4 ~]$ echo " file created for TEE command" | tee teefile1.txt teefile2.txt teefile3.txt

file created for TEE command

[haritaraka12078@cxln4 ~]$ cat teefile1.txt teefile2.txt teefile3.txt

file created for TEE command

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Write to a privileged file

-----------------------------------------------------------------------------------------------------------

The tee command allows us to write to a file having sudo privilege.
If we try to write a file owned by the root user will through the permission error.

But, we can elevate the sudo permission by executing the tee command as follows:

[haritaraka12078@cxln4 ~]$ echo "some text for privileged file" | sudo tee -a teefile6.txt

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Ignoring Interrupts

-----------------------------------------------------------------------------------------------------------

The '-i' option is used to ignore the interrupts.

command | tee -i teefile3.txt

Hide the output

To restrict the tee command not to write to the standard output, redirect it to "/dev/null".

[haritaraka12078@cxln4 ~]$ echo "Text" | tee teefile7.txt >/dev/null

[haritaraka12078@cxln4 ~]$ cat teefile7.txt

Text

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'TR' Command

The command 'tr' stands for 'translate'. It is used to translate, like from lowercase to uppercase and vice versa or new lines into spaces.

command | tr <'old'> <'new'>

[haritaraka12078@cxln4 ~]$ cat exm.txt | tr 'prcu' 'PRCU'

aPPle is Red

mango is yellow

yoUR dRess ColoR is Red

blaCk ColoR sUits yoU all

Note: all p,r,c,u are converted into upprecase P,R,C,U.

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Remove New Lines

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To write all the lines into a single line we have to translate all new lines into spaces.

command | tr <'\n'> <' '>

[haritaraka12078@cxln4 ~]$ cat>jtp.txt

hellllllllllllllllllooooooooooooo

allllllllllllllll

[haritaraka12078@cxln4 ~]$ cat jtp.txt | tr -s 'l'

helooooooooooooo

[haritaraka12078@cxln4 ~]$ cat>spaces.tst

a b c d

e f g h

[haritaraka12078@cxln4 ~]$ cat spaces.tst | tr -s ' '

a b c d

e f g h

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tr Options

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tr -s : The 'tr -s' command squeezes the occurence of multiple characters into one.

Syntax: command | tr -s <'letter'>

tr rot13: This command encrypts the text. It is case-sensitive

[haritaraka12078@cxln4 ~]$ cat exm.txt | tr 'a-z' 'nopqrstuvwxyzabcdefghijklm'

nccyr vf erq

znatb vf lryybj

lbhe qerff pbybe vf erq

oynpx pbybe fhvgf lbh nyy

[haritaraka12078@cxln4 ~]$ cat exm.txt | tr 'a-z' 'n-za-m'

nccyr vf erq

znatb vf lryybj

lbhe qerff pbybe vf erq

oynpx pbybe fhvgf lbh nyy

[haritaraka12078@cxln4 ~]$

tr -d: The 'tr -d' command is used to delete characters.

[haritaraka12078@cxln4 ~]$ cat exm.txt | tr -d o

apple is red

mang is yellw

yur dress clr is red

black clr suits yu all

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'UNIQ' Command

Linux uniq command is used to remove all the repeated lines from a file. Also, it can be used to display a count of any word, only repeated lines, ignore characters, and compare specific fields. It is one of the most frequently used commands

in the Linux system. It is often used with the sort command

Syntax:

uniq [OPTION]... [INPUT [OUTPUT]]

Options:

-c, --count: it prefixes the lines by the number of occurrences.
-d, --repeated: it is used to print duplicate lines, one for each group.
-D: It is used to print all the duplicate lines.
--all-repeated[=METHOD]: It is quite similar to the '-D' option, the difference between both the options is that it allows separation of groups with an empty line.
-f, --skip-fields=N: It is used to avoid comparison of the first N fields.
--group[=METHOD]: It is used to display all items and separates the groups with an empty line.
-i, --ignore-case: It is used to ignore the differences while comparing.
-s, --skip-chars=N: It is used to avoid the comparison of the first N characters.
-u, --unique: it is used to print unique lines.
-z, --zero-terminated: It is used for the line delimiter is NUL and not newline mode.
-w, --check-chars=N: It is used to compare not more than N characters in lines.
--help: It is used to display help documentation.
--version: It is used to display the version information.

[haritaraka12078@cxln4 ~]$ cat weeks.txt

sunday

tuesday

wednesday

saturday

sunday

tuesday

wednesday

saturday

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Remove repeated lines

-----------------------------------------------------------------------------------------------------------

[haritaraka12078@cxln4 ~]$ sort weeks.txt | uniq

saturday

sunday

tuesday

wednesday

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Count the number of occurrences of a word

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[haritaraka12078@cxln4 ~]$ sort weeks.txt | uniq -c

2 saturday

2 sunday

2 tuesday

2 wednesday

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Display the repeated lines

-----------------------------------------------------------------------------------------------------------

[haritaraka12078@cxln4 ~]$ sort weeks.txt | uniq -d

saturday

sunday

tuesday

wednesday

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Display the unique lines

-----------------------------------------------------------------------------------------------------------

The '-u' option is used to display only the unique lines ( which are not repeated). It will only display the lines that occur only once and write the result to standard output. Consider the below command:

sort dupli.txt | uniq -u

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Ignore characters in comparison

-----------------------------------------------------------------------------------------------------------

The '-s' option is used to ignore the characters in comparison. It will ignore the specified number of characters

[haritaraka12078@cxln4 ~]$ sort weeks.txt | uniq -s 2

saturday

sunday

tuesday

wednesday

-----------------------------------------------------------------------------------------------------------

Ignore fields in comparison

-----------------------------------------------------------------------------------------------------------

The '-f' option is used to ignore the field

[haritaraka12078@cxln4 ~]$ uniq -f 2 weeks.txt

sunday

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'WC' Command

Linux wc command helps in counting the lines, words, and characters in a file.
It displays the number of lines, number of characters, and the number of words in a file.
Mostly, it is used with pipes for counting operation.

Options:

-c, --bytes: It is used to print the byte counts.
-m, --chars: It is used to print the character counts.
-l, --lines: It is used to print the newline counts.
--files0-from=F: It is used to read input from specified files.
-L, --max-line-length: It is used to print the maximum display width.
-w, --words: It is used to print the word counts.
--help: It is used to display the help manual.
--version: It is used to display the version information.

----------------------------------------------------------------------------

---------->>Display count information of a file

----------------------------------------------------------------------------

[haritaraka12078@cxln4 ~]$ wc exm.txt

4 16 79 exm.txt

Note:

4-no of lines

16- no of words

79 - no of bytes

----------------------------------------------------------------------------

---------------->> Multiple files count

----------------------------------------------------------------------------

[haritaraka12078@cxln4 ~]$ wc exm.txt marks.txt

4 16 79 exm.txt

9 21 134 marks.txt

13 37 213 total

----------------------------------------------------------------------------

---------->> no of lines

----------------------------------------------------------------------------

[haritaraka12078@cxln4 ~]$ wc -l exm.txt

4 exm.txt

----------------------------------------------------------------------------

----> no of charecters

----------------------------------------------------------------------------

[haritaraka12078@cxln4 ~]$ wc -m exm.txt

79 exm.txt

----------------------------------------------------------------------------

----->> no of bytes

----------------------------------------------------------------------------

[haritaraka12078@cxln4 ~]$ wc -c exm.txt

79 exm.txt

----------------------------------------------------------------------------

- no of charcters

----------------------------------------------------------------------------

[haritaraka12078@cxln4 ~]$ wc -w exm.txt

16 exm.txt

----------------------------------------------------------------------------

- no of files in directory

----------------------------------------------------------------------------

[haritaraka12078@cxln4 ~]$ ls | wc -l

[haritaraka12078@cxln4 ~]$ wc -L exm.txt

25 exm.txt

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'OD' Command

The 'od' term stands for octal dump.
It displays content of a file in different human-readable formats like hexadecimal, octal and ASCII characters.

Syntax:

od -b <fileName> (display files in octal format)

od -t x1 <fileName> (display files in hexadecimal bytes format)

od -c <fileName> (display files in ASCII (backslashed) character format)

[haritaraka12078@cxln4 ~]$ cat format.txt

abcdefghi

123456789

[haritaraka12078@cxln4 ~]$ od -b format.txt

0000000 141 142 143 144 145 146 147 150 151 012 061 062 063 064 065 066

0000020 067 070 071 012

0000024

[haritaraka12078@cxln4 ~]$ od -t x1 format.txt

0000000 61 62 63 64 65 66 67 68 69 0a 31 32 33 34 35 36

0000020 37 38 39 0a

0000024

[haritaraka12078@cxln4 ~]$ od -c format.txt

0000000 a b c d e f g h i \n 1 2 3 4 5 6

0000020 7 8 9 \n

0000024

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'SORT Command

The 'sort' command sorts the file content in an alphabetical order

[haritaraka12078@cxln4 ~]$ cat name.txt

hari prabhu

manyam taraka

siva teja

sunny ayyappa

lucky pinky

[haritaraka12078@cxln4 ~]$ sort name.txt

hari prabhu

lucky pinky

manyam taraka

siva teja

sunny ayyappa

--------------------------------------------------------------------------------------

---To Sort A Column

--------------------------------------------------------------------------------------

[haritaraka12078@cxln4 ~]$ sort -k1 name.txt

hari prabhu

lucky pinky

manyam taraka

siva teja

sunny ayyappa

[haritaraka12078@cxln4 ~]$ sort -k2 name.txt

sunny ayyappa

lucky pinky

hari prabhu

manyam taraka

siva teja

--------------------------------------------------------------------------------------

-------------Numeric Sorting

--------------------------------------------------------------------------------------

[haritaraka12078@cxln4 ~]$ sort -n -k2 mark.txt

tarka 5

prabhu 10

sunny 25

hari 50

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'GZIP Command

Gzip (GNU zip) is a compressing tool, which is used to truncate the file size. By default original file will be replaced by the compressed file ending with extension (.gz).

To decompress a file you can use gunzip command and your original file will be back.

Syntax:

gzip <file1> <file2> <file3>. . .

gunzip <file1> <file2> <file3>. . .

Example:

gzip file1.txt file2.txt

gunzip file1.txt file2.txt

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More than one file compressing :

-------------------------------------------------------

cat file1.txt file2.txt | gzip > final.gz

-------------------------------------------------------

gzip -i --> compression ratio or how much the original file has compressed.

-------------------------------------------------------

gzip -l final.gz jtp.txt.gz

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How To Compress A Directory

-------------------------------------------------------

The gzip command will not be able to compress a directory because it can only compress a single file.
To compress a directory you have to use 'tar' command.
Hyphen (-) is not mandatory in 'tar' command.

Options:

'c' is to create,
'v' is for verbose, to display output,
'f' to mention destination of your output file,
'z' for specifying compress with gzip.

Syntax:

tar cf - <directory> | gzip > <directoryName>

tar cf - office | gzip > office.tar.gz

Q A - Z O N E

Pages

FILTER Commands

FILTER Commands

FMT

CAT

COMM

SED

TEE Command

'TR' Command

Syntax: command | tr -s <'letter'>

tr rot13: This command encrypts the text. It is case-sensitive

'UNIQ' Command

Syntax:

Options:

'WC' Command

'OD' Command

'SORT Command

'GZIP Command