cut (extract columns) in Linux CLI - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

Extract specific columns using cut

Given a file data.txt with the following content:

apple,banana,cherry,date
red,yellow,red,brown
sweet,sweet,tart,sweet

What is the output of the command cut -d',' -f2,4 data.txt?

A

apple,cherry
date,red
red,tart

B

banana,date
yellow,brown
sweet,tart

C

banana,date
red,brown
sweet,sweet

D

banana,date
yellow,brown
sweet,sweet

💡 Hint

Remember that -d sets the delimiter and -f selects fields by their position.

The command uses comma as delimiter and extracts fields 2 and 4 from each line. So from the first line, 'banana' and 'date' are extracted, and similarly for other lines.

💻 Command Output

intermediate

Using cut with byte positions

Consider a file file.txt containing:

abcdefg
hijklmn
opqrstu

What is the output of cut -b2-4 file.txt?

A

bcd
ijk
pqr

B

abc
hij
opq

C

bcd
hij
pqr

D

bcd
ijk
opq

💡 Hint

The -b option extracts bytes by position, starting at 1.

The command extracts bytes 2 to 4 from each line. For 'abcdefg', bytes 2-4 are 'bcd', for 'hijklmn' they are 'ijk', and for 'opqrstu' they are 'pqr'.

🔧 Debug

advanced

Identify the error in cut command usage

What error will the command cut -f1-3 -d',' file.csv produce if file.csv contains tab-separated values instead of commas?

A cut: file.csv: No such file or directory

B No output because no delimiter ',' found, so entire lines are printed

C cut: invalid delimiter ','

D cut: field list syntax error

💡 Hint

Think about what happens if the delimiter does not match the file content.

If the delimiter specified does not exist in the file, cut treats the entire line as one field and prints it entirely. No error is raised.

🚀 Application

advanced

Extract columns with multiple delimiters

You have a file records.txt with lines like:

name|age,city|country
Alice|30,New York|USA
Bob|25,London|UK

Which command extracts the 'age' and 'country' fields correctly?

A cut -d'|' -f2 records.txt | cut -d',' -f2

B cut -d',' -f1 records.txt | cut -d'|' -f2

C cut -d'|' -f2,4 records.txt

D cut -d',' -f2,4 records.txt

💡 Hint

Try to split first by one delimiter, then by the other.

First, splitting by '|' and taking field 2 extracts 'age,city'. Then cutting that by ',' and taking field 2 extracts 'city' or 'country' depending on position. Here, the second cut extracts 'country' from the second delimiter-separated part.

🧠 Conceptual

expert

Understanding cut behavior with multibyte characters

Given a file utf8.txt containing:

café
naïve
jalapeño

What is the output of cut -b1-4 utf8.txt?

A

caf
naï
jala

B

café
naïv
jala

C

caf�
naï
jala

D

alaj
vïan
éfac

💡 Hint

Remember that cut -b counts bytes, not characters, and UTF-8 characters can be multiple bytes.

The accented characters like 'é' and 'ï' use multiple bytes in UTF-8. Cutting by bytes can split these characters, resulting in invalid byte sequences shown as replacement characters (�).