Linux Unix Cut Command

The cut command is used for text processing. It is a command line utility. You can use this command to extract portions of text from a file.

Selection can be done on:

• characters using -c option.
• columns using -d and -f options.
• bytes using -b option.

The cutcommand selects sections from each line of the input stream and sends the result to the standard output.

Let's create a simple file named 'cut.txt' to test this command:

cat > cut.txt << EOF
Luka:M:14
Mathias:M:11
Jules:M:11
Eloise:F:5
Thibaud:M:3
Nina:F:11
Zoe:F:15
Gaspard:M:6
EOF

Learning from examples

How to cut according to characters

The -c option cuts (selects) specific characters.

To select the second character:

cut -c2 cut.txt

u
a
u
l
h
i
o
a

To select a range of characters for example:

• From the second character to the fifth 2-5

cut -c2-5 cut.txt

uka:
athi
ules
lois
hiba
ina:
oe:F
aspa

• From the second character to the end of each line (the second term of the range is omitted: 2-:)

cut -c2- cut.txt

uka:M:14
athias:M:11
ules:M:11
loise:F:5
hibaud:M:3
ina:F:11
oe:F:15
aspard:M:6

• Eight characters (including blank characters) from the beginning of each line (the first term of the range is omitted: -8)

cut -c-8 cut.txt

Luka:M:1
Mathias:
Jules:M:
Eloise:F
Thibaud:
Nina:F:1
Zoe:F:15
Gaspard:

How to cut according to a delimiter :

• The -d option specifies the delimiter in the file. The delimiter can be set to a comma ',' or ':' or ' ', etc.
• The -f option indicates the number of the field(s) to be cut

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

14
11
11
5
3
11
15
6

To select more than one column

cut -d ':' -f 1,4 cut.txt

Luka
Mathias
Jules
Eloise
Thibaud
Nina
Zoe
Gaspard

To select a range of columns

cut -d ':' -f 2-3 cut.txt
e```
## How to modify the output delimiter

The `--output-delimiter` option specifies the output delimiter.

M:14
M:11
M:11
F:5
M:3
F:11
F:15
M:6
bash: -c: line 4: unexpected EOF while looking for matching ``'
bash: -c: line 5: syntax error: unexpected end of file

cut -d ':' -f 1,3 --output-delimiter=' ' cut.txt

Luka 14
Mathias 11
Jules 11
Eloise 5
Thibaud 3
Nina 11
Zoe 15
Gaspard 6

How to cut the complement characters

• The -c 2 option is used to cut the second character from each line
• the --complementécole option specifies to cut the complement of the -c2 option

cut --complement -c 2 cut.txt

Lka:M:14
Mthias:M:11
Jles:M:11
Eoise:F:5
Tibaud:M:3
Nna:F:11
Ze:F:15
Gspard:M:6

How to cut according to byte positions

To cut out a section by specifying byte positions use the -b option.

echo 'great' | cut -b 1-4

grea

echo 'école' | cut -b 1-2

é

The cut command is based on the range of bytes and it is not necessarily equal to the number of characters. Accentuated letters as 'é' are encoded on two bytes. This explains why the result is just one character in this case.