Bash cut - Remove Sections from Each Line of Files
Using the cut Command
The cut command is used to remove sections from each line of files.
It's a useful tool for extracting specific fields of data from a file or output stream.
All examples below use the example_data.txt file:
Kai Refsnes 30,Norway
Robin Smith 25,Denmark
Sienna Davis 40,GermanyBasic Usage
To extract the first field of a file, use cut -f1 filename:
Example: Extract First Field
cut -f1 example_data.txt
Kai
Robin
SiennaBy default, cut uses a tab as the delimiter.
Options
The cut command has options to change how it works:
-d- Choose what separates the fields-f- Select specific fields to display--complement- Show all fields except the selected ones
Specify a Delimiter
The -d option allows you to choose what separates the fields.
Example: Specify a Delimiter
cut -d',' -f1 example_data.txt
Kai Refsnes 30
Robin Smith 25
Sienna Davis 40Select Specific Fields
The -f option allows you to select specific fields to display.
Example: Select Specific Fields
cut -f1-2 example_data.txt
Kai Refsnes
Robin Smith
Sienna DavisShow Complement
The --complement option allows you to show all fields except the selected ones.
Example: Show Complement
cut --complement -f1 example_data.txt
Refsnes 30,Norway
Smith 25,Denmark
Davis 40,GermanyAdvanced Field Extraction
Cut can perform advanced field extraction tasks.
For example, cut -d' ' -f2-3 example_data.txt extracts fields 2 through 3 from the file.
Example: Advanced Field Extraction
cut -f2-3 example_data.txt
Refsnes 30,Norway
Smith 25,Denmark
Davis 40,GermanyCommon Errors and Troubleshooting
When using cut, you might encounter errors such as:
- "cut: delimiter must be a single character" - Ensure the delimiter is correctly specified.
- "cut: fields and positions are numbered from 1" - Remember that field and position numbering starts at 1.
Debugging tips include checking the delimiter and field specifications to ensure they match the file's format.
