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====== BASH - Commands - cut ======

**cut** allows cutting of sections based on byte positions, characters, or fields separated by a delimiter like the ‘-‘ or ‘:’ characters. 

cut can remove sections from each line of a file.

**cut** can return sections based on number of bytes (-b), characters (-c), or fields (-f) when fields are separated by a delimiter(-d).

<WRAP info>
Default delimiter is tab.
</WRAP>

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[[BASH:Commands:cut:Cut using Bytes|Cut using Bytes]]

[[BASH:Commands:cut:Cut using Characters|Cut using Characters]]

[[BASH:Commands:cut:Cut using Fields|Cut using Fields]]


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===== Miscellaneous =====

===== Inspect The passwd File Using Cut Command =====

<code bash>
cut -d ':' -f1 /etc/passwd
</code>

The passwd file stored inside /etc in most systems contain very sensitive information about the system and its users.

You can inspect this file quickly using the cut command.

Delimiter ‘:’ is used as the columns of this file are separated using it.

Change the value of -f to monitor different fields.

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===== Cut Specific Fields and Show Only the Unique Entries =====

<code bash>
cut -d ':' -f 3 test.txt | uniq -u
</code>

Cut the third column of the file test.txt and only show the unique entries.

----

===== Cut All Bytes of Input Stream Except the Specified Ones =====

<code bash>
echo "Let's cut this input stream section by section" | cut -b 1,3,5,7 --complement
</code>

Cut all the characters of the given input string except the ones supplied to -b.

So, byte positions first, third, fifth, and seventh will be omitted from the output.

----

===== Cut All Bytes of a File Except the Specified Ones =====

<code bash>
cut -b 2,4,6 test.txt --complement
</code>

Cut all the bytes of the file test.txt except the one mentioned in the command.

Thus, the output will not contain the second, fourth, and sixth bytes of each line.

----

===== Cut All Characters of Input Stream Except the Specified Ones =====

<code bash>
echo "Let's cut this input stream section by section" | cut -c 1,3,5,7 --complement
</code>

This command refrains from cutting the first, third, fifth, and seventh characters of the input string and instead cuts all other characters except these four.

----

===== Cut All Characters of a File Except the Specified Ones =====

<code bash>
cut -c 2,4,6 test.txt --complement
</code>

The output will contain all characters of the test.txt files except the ones mentioned.

So, characters second, fourth, and sixth will not be displayed.

----

===== Cut all Input Sections Except the Ones Specified =====

<code bash>
echo "Let's cut this input stream section by section" | cut -d ' ' -f 1,3,5 --complement
</code>

Output the string “cut input section by section“.

So, it will display all the input sections without the ones mentioned after the field flag.

----

===== Cut All Columns of a File Except the Specified Ones =====

<code bash>
cut -d ':' -f 2,3 test.txt --complement
</code>

Cut only the first and last columns of the file test.txt.

So, you can easily deselect some fields when processing large tabular documents using the complement flag.

----

===== Cut a Section of Input and Reverse them Characterwise =====

<code bash>
echo "Let's cut this input stream section by section" | rev | cut -d ' ' -f 1,3
</code>

Cut the first and third section of the input and reverse them characterwise.

Notice, how the output of one command is being fed as the input to other commands.

----

===== Cut Specific Columns in a File and Reverse them Characterwise =====

<code bash>
cut -d ':' -f 1,3 test.txt | rev
</code>

Cut the specified fields of the file test.txt and display the result in a characterwise reverse manner.

----

===== Modify the Output Delimiter of the Cut Command =====

<code bash>
echo "A,comma,separated,list,for,demonstration,purposes" | cut -d ',' -f 1- --output-delimiter=' '
</code>

Cut allows us to modify the output delimiter when displaying the result.

Cuts all sections of the comma-separated list but replaces the commas with spaces when showing the result.

----

===== Example of Cut+Sed Command with Tab Delimiter =====

<code bash>
sed 's/:/\t/g' test.txt | cut -f 1-4
</code>

Replace the colons in our file with tabs.

You can replace \t with some other characters like – or ; for changing to an output delimiter of your choice.