How to use the Linux cut command with a field and delimiter

Should you ever run into a situation where you want to use the Linux cut command by specifying both a field number and field delimiter, I hope this example is helpful for you.

I was just working on a problem where I wanted to list all the fonts on a Mac OS X (Unix) system, and needed to use the cut command this way. A straight listing of all the filenames in the Mac font directory gave me a long list of names like this:

$ ls -1

AScore.ttf.11904_0.ATSD
AScore.ttf.11904_0.fontinfo
AScoreParts.ttf.122A0_0.ATSD
AScoreParts.ttf.122A0_0.fontinfo
Abadi MT Condensed Extra Bold.0_11005.ATSD
Abadi MT Condensed Extra Bold.0_11005.fontinfo

(There are actually 761 files on my current system, so I omitted a lot of output.)

For my needs, I just wanted the first part of each filename, i.e., the text string to the left of the first decimal in each filename, like this:

AScore
AScoreParts
Abadi MT Condensed Extra Bold

In short, to create this list, I used the following Unix cut command, specifying the desired field number and field delimiter:

$ ls -1 | cut -f1 -d'.'

This command can be read like this:

◉ Create a single column list of all files in the current directory.

◉ From that list, only print the first field of each filename, where the field delimiter is the "." character.

Running this command gave me the output I wanted:

AScore
AScoreParts
Abadi MT Condensed Extra Bold

More cut command examples

As a few more quick cut command examples, had I wanted to print the second field of each filename, I would have used this command:

$ ls -1 | cut -f2 -d'.'

If it made sense to use a space as the field delimiter, my cut command would have looked like this:

$ ls -1 | cut -f2 -d' '

And for something a little different, if I wanted to print all the usernames out of the /etc/passwd file on my Unix system, I can use this cut command:

$ cut -f1 -d: /etc/passwd

In that example, I'm again printing field one, but this time I'm using the ":" character as the field delimiter, and I'm reading directly from a file named /etc/passwd, instead of reading from standard input.

Continue reading

Unix/Linux ‘cut’ command examples

Linux cut command FAQ: Can you share some cut command examples?

The Linux cut command is a really great command filter to know. You can use it to do all sorts of cool things when processing text files and text in command pipelines.

Using the cut command with /etc/passwd

For a first cut command example, I'll use the /etc/passwd file on my Unix system. I use this file because fields in the file are separated by the ":" character, which make it very easy to work with.

Using that file, here's a Linux cut command that prints the first field (first column) of every line in that file:

cut -f1 -d: /etc/passwd

This cut command can be read as:

◉ Print the first field (-f1)
◉ Fields are delimited by the ":" character (-d:)
◉ Use the /etc/passwd file as input

The output of this command will vary by Unix and Linux systems, but it will be the first field of your /etc/passwd file, which contains the name of the users on your system. This will look something like:

nobody
lpi
george
fred

and so on.

Using the cut command in a command pipeline

You can also use cut in a Unix/Linux command pipeline. For example, although you can get this information in other ways, you can use the cut command with the ls command to get a list of filenames in the current directory, like this:

ls -al | cut -c44-

Notice that in this command I'm using the cut command "-c" option. This command can be read as:

◉ Run the "ls -al" command
◉ Pipe the output of that command into cut
◉ The cut command prints everything from each line starting at column 44 through the end of the line (-c44-)

As you can see, the -c option lets you deal with columns or character positions. In this example I wanted all the output from each line starting in column 44 and going to the end of the line, but if I wanted only columns 40 through 50, I could have specified that like this instead:

ls -al | cut -c44-50

That particular command doesn't make much sense in the real world, since filenames can all be different lengths, but it does show how to use a range of columns with the Linux cut command.

More Unix cut command examples

There are many other uses of the Unix cut command, but I wanted to share these with you to get started. The cut command is a great Unix shell script tool, and I highly recommend being familiar with it.

Continue reading

cut command in Linux with examples

The cut command in UNIX is a command for cutting out the sections from each line of files and writing the result to standard output. It can be used to cut parts of a line by byte position, character and field. Basically the cut command slices a line and extracts the text. It is necessary to specify option with command otherwise it gives error. If more than one file name is provided then data from each file is not precedes by its file name.

Syntax:

cut OPTION... [FILE]...

Let us consider two files having name state.txt and capital.txt contains 5 names of the Indian states and capitals respectively.

$ cat state.txt
Andhra Pradesh
Arunachal Pradesh
Assam
Bihar
Chhattisgarh

Without any option specified it displays error.

$ cut state.txt
cut: you must specify a list of bytes, characters, or fields
Try 'cut --help' for more information.

Options and their Description with examples:

1. -b(byte): To extract the specific bytes, you need to follow -b option with the list of byte numbers separated by comma. Range of bytes can also be specified using the hyphen(-). It is necessary to specify list of byte numbers otherwise it gives error. Tabs and backspaces are treated like as a character of 1 byte.

List without ranges
$ cut -b 1,2,3 state.txt
And
Aru
Ass
Bih
Chh

List with ranges
$ cut -b 1-3,5-7 state.txt
Andra
Aruach
Assm
Bihr
Chhtti

It uses a special form for selecting bytes from beginning upto the end of the line:

In this, 1- indicate from 1st byte to end byte of a line
$ cut -b 1- state.txt
Andhra Pradesh
Arunachal Pradesh
Assam
Bihar
Chhattisgarh

In this, -3 indicate from 1st byte to 3rd byte of a line
$ cut -b -3 state.txt
And
Aru
Ass
Bih
Chh

2. -c (column): To cut by character use the -c option. This selects the characters given to the -c option. This can be a list of numbers separated comma or a range of numbers separated by hyphen(-). Tabs and backspaces are treated as a character. It is necessary to specify list of character numbers otherwise it gives error with this option.

Syntax:

$cut -c [(k)-(n)/(k),(n)/(n)] filename

Here,k denotes the starting position of the character and n denotes the ending position of the character in each line, if k and n are separated by “-” otherwise they are only the position of character in each line from the file taken as an input.

$ cut -c 2,5,7 state.txt
nr
rah
sm
ir
hti

Above cut command prints second, fifth and seventh character from each line of the file.

$ cut -c 1-7 state.txt
Andhra
Arunach
Assam
Bihar
Chhatti

Above cut command prints first seven characters of each line from the file.

Cut uses a special form for selecting characters from beginning upto the end of the line:

$ cut -c 1- state.txt
Andhra Pradesh
Arunachal Pradesh
Assam
Bihar
Chhattisgarh

Above command prints starting from first character to end. Here in command only starting
position is specified and the ending position is omitted.

$ cut -c -5 state.txt
Andhr
Aruna
Assam
Bihar
Chhat

Above command prints starting position to the fifth character. Here the starting position
is omitted and the ending position is specified.

3. -f (field): -c option is useful for fixed-length lines. Most unix files doesn’t have fixed-length lines. To extract the useful information you need to cut by fields rather than columns. List of the fields number specified must be separated by comma. Ranges are not described with -f option. cut uses tab as a default field delimiter but can also work with other delimiter by using -d option.

Note: Space is not considered as delimiter in UNIX.

Syntax:

$cut -d "delimiter" -f (field number) file.txt

Like in the file state.txt fields are separated by space if -d option is not used then it prints whole line:

$ cut -f 1 state.txt
Andhra Pradesh
Arunachal Pradesh
Assam
Bihar
Chhattisgarh

If -d option is used then it considered space as a field separator or delimiter:

$ cut -d " " -f 1 state.txt
Andhra
Arunachal
Assam
Bihar
Chhattisgarh

Command prints field from first to fourth of each line from the file.
Command:
$ cut -d " " -f 1-4 state.txt
Output:
Andhra Pradesh
Arunachal Pradesh
Assam
Bihar
Chhattisgarh

4. –complement: As the name suggests it complement the output. This option can be used in the combination with other options either with -f or with -c.

$ cut --complement -d " " -f 1 state.txt
Pradesh
Pradesh
Assam
Bihar
Chhattisgarh

$ cut --complement -c 5 state.txt
Andha Pradesh
Arunchal Pradesh
Assa
Biha
Chhatisgarh

5. –output-delimiter: By default the output delimiter is same as input delimiter that we specify in the cut with -d option. To change the output delimiter use the option –output-delimiter=”delimiter”.

$ cut -d " " -f 1,2 state.txt --output-delimiter='%'
Andhra%Pradesh
Arunachal%Pradesh
Assam
Bihar
Chhattisgarh

Here cut command changes delimiter(%) in the standard output between the fields which is specified by using -f option .

6. –version: This option is used to display the version of cut which is currently running on your system.

$ cut --version
cut (GNU coreutils) 8.26
Packaged by Cygwin (8.26-2)
Copyright (C) 2016 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later .
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Applications of cut Command

1. How to use tail with pipes(|): The cut command can be piped with many other commands of the unix. In the following example output of the cat command is given as input to the cut command with -f option to sort the state names coming from file state.txt in the reverse order.

$ cat state.txt | cut -d ' ' -f 1 | sort -r
Chhattisgarh
Bihar
Assam
Arunachal
Andhra

It can also be piped with one or more filters for additional processing. Like in the following example, we are using cat, head and cut command and whose output is stored in the file name list.txt using directive(>).

$ cat state.txt | head -n 3 | cut -d ' ' -f 1 > list.txt

$ cat list.txt
Andhra
Arunachal
Assam

Continue reading

Cut Command in Unix ( Linux) Examples

Cut command in unix (or linux) is used to select sections of text from each line of files. You can use the cut command to select fields or columns from a line by specifying a delimiter or you can select a portion of text by specifying the range or characters. Basically the cut command slices a line and extracts the text.

Unix Cut Command Example

We will see the usage of cut command by considering the below text file as an example

> cat file.txt
unix or linux os
is unix good os
is linux good os

1. Write a unix/linux cut command to print characters by position?

The cut command can be used to print characters in a line by specifying the position of the characters. To print the characters in a line, use the -c option in cut command

cut -c4 file.txt
x
u
l

The above cut command prints the fourth character in each line of the file. You can print more than one character at a time by specifying the character positions in a comma separated list as shown in the below example

cut -c4,6 file.txt
xo
ui
ln

This command prints the fourth and sixth character in each line.

2 .Write a unix/linux cut command to print characters by range?

You can print a range of characters in a line by specifying the start and end position of the characters.

cut -c4-7 file.txt
x or
unix
linu

The above cut command prints the characters from fourth position to the seventh position in each line. To print the first six characters in a line, omit the start position and specify only the end position.

cut -c-6 file.txt
unix o
is uni
is lin

To print the characters from tenth position to the end, specify only the start position and omit the end position.

cut -c10- file.txt
inux os
ood os
good os

If you omit the start and end positions, then the cut command prints the entire line.

cut -c- file.txt

3. Write a unix/linux cut command to print the fields using the delimiter?

You can use the cut command just as awk command to extract the fields in a file using a delimiter. The -d option in cut command can be used to specify the delimiter and -f option is used to specify the field position.

cut -d' ' -f2 file.txt
or
unix
linux

This command prints the second field in each line by treating the space as delimiter. You can print more than one field by specifying the position of the fields in a comma delimited list.

cut -d' ' -f2,3 file.txt
or linux
unix good
linux good

The above command prints the second and third field in each line.

Note: If the delimiter you specified is not exists in the line, then the cut command prints the entire line. To suppress these lines use the -s option in cut command.

4. Write a unix/linux cut command to display range of fields?

You can print a range of fields by specifying the start and end position.

cut -d' ' -f1-3 file.txt

The above command prints the first, second and third fields. To print the first three fields, you can ignore the start position and specify only the end position.

cut -d' ' -f-3 file.txt

To print the fields from second fields to last field, you can omit the last field position.

cut -d' ' -f2- file.txt

5. Write a unix/linux cut command to display the first field from /etc/passwd file?

The /etc/passwd is a delimited file and the delimiter is a colon (:). The cut command to display the first field in /etc/passwd file is

cut -d':' -f1 /etc/passwd

6. The input file contains the below text

> cat filenames.txt
logfile.dat
sum.pl
add_int.sh

Using the cut command extract the portion after the dot.

First reverse the text in each line and then apply the command on it.

rev filenames.txt | cut -d'.' -f1

Continue reading