cut is a Linux command utility for cutting sections of text from each line of files. Examples of cutting by character, byte position, cutting based on delimiter and how to modify the output delimiter.
The cut command in UNIX is a command line utility for cutting sections from each line of files and writing the result to standard output. It can be used to cut parts of a line by byte position, character and delimiter. It can also be used to cut data from file formats like CSV.
How to cut by byte position
To cut out a section of a line by specifying a byte position use the -b option.
echo 'baz' | cut -b 2
a
echo 'baz' | cut -b 1-2
ba
echo 'baz' | cut -b 1,3
bz
How to cut by character
To cut by character use the -c option. This selects the characters given to the -c option. This can be a list of comma separated numbers, a range of numbers or a single number.
Where your input stream is character based -c can be a better option than selecting by bytes as often characters are more than one byte.
In the following example character ‘♣’ is three bytes. By using the -c option the character can be correctly selected along with any other characters that are of interest.
echo '♣foobar' | cut -c 1,6
♣a
echo '♣foobar' | cut -c 1-3
♣fo
How to cut based on a delimiter
To cut using a delimiter use the -d option. This is normally used in conjunction with the -f option to specify the field that should be cut.
In the following example a CSV file exists and is saved as names.csv.
John,Smith,34,London
Arthur,Evans,21,Newport
George,Jones,32,Truro
The delimiter can be set to a comma with -d ','. cut can then pull out the fields of interest with the -f flag. In the following example the first field is cut.
cut -d ',' -f 1 names.csv
John
Arthur
George
Multiple fields can be cut by passing a comma separated list.
cut -d ',' -f 1,4 names.csv
John,London
Arthur,Newport
George,Truro
How to cut by complement pattern
To cut by complement us the --complement option. Note this option is not available on the BSD version of cut. The --complement option selects the inverse of the options passed to cut.
In the following example the -c option is used to select the first character. Because the --complement option is also passed to cut the second and third characters are cut.
echo 'foo' | cut --complement -c 1
oo
How to modify the output delimiter
To modify the output delimiter use the --output-delimiter option. Note that this option is not available on the BSD version of cut. In the following example a semi-colon is converted to a space and the first, third and fourth fields are selected.
echo 'how;now;brown;cow' | cut -d ';' -f 1,3,4 --output-delimiter=' '
how brown cow
