Understanding the Cut Command

The cut command is a powerful utility in Unix-like operating systems used for selecting columns of text from each line of a file. It's particularly useful for extracting specific data fields or characters from structured text files. If you require more comprehensive pattern-directed scanning and processing, consider using awk.

Selecting Characters with Cut

You can use the -c option to specify character positions. For example, given a text file (file.txt) with the following content:

unix or linux os
is unix good os
is linux good os

Extracting a Single Character

To extract the fourth character from each line:

cut -c4 file.txt

Output:

x
u
l

Extracting Multiple Characters

To extract the fourth and sixth characters:

cut -c4,6 file.txt

Output:

xo
ui
ln

Extracting a Range of Characters

To extract characters from the fourth through the seventh:

cut -c4-7 file.txt

Output:

x or
unix
linu

Selecting Fields with Delimiters

The cut command can also operate on fields (columns) separated by a delimiter. Use the -d option to specify the delimiter and -f to specify the field number.

Extracting the Second Field

To extract the second element, delimited by a space:

cut -d' ' -f2 file.txt

Output:

or
unix
linux

Extracting Multiple Fields

Similarly, you can extract multiple fields. To get the second and third fields:

cut -d' ' -f2,3 file.txt

Output:

or linux
unix good
linux good

Further Resources

• Official cut man page
• GNU Coreutils cut documentation
• Stack Overflow discussions on cut