linux cut 命令

cut , a UNIX and Linux command for cutting sections from each line of files.

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

use the -b option.

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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

use the -c option.

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.

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echo '♣foobar' | cut -c 1,6
♣a
echo '♣foobar' | cut -c 1-3
♣fo

How to cut based on a delimiter

use the -d option. This is normally used in conjunction with the -f option to specify the field that should be cut.

  • names.csv 
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      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.

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cut -d ',' -f 1 names.csv
John
Arthur  
George

Multiple fields can be cut by passing a comma separated list.

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cut -d ',' -f 1,4 names.csv
John,London
Arthur,Newport
George,Truro

包括第二个字段以后所有字段

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cut -d ',' -f 2- names.csv

Smith,34,London
Evans,21,Newport
Jones,32,Truro

How to cut by complement pattern (not available on the BSD)

use the --complement option. The --complement option selects the inverse of the options passed to sort.

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echo 'foo' | cut --complement -c 1
oo

How to modify the output delimiter (not available on the BSD)

To modify the output delimiter use the --output-delimiter option.

In the following example a semi-colon is converted to a space and the first, third and fourth fields are selected.

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echo 'how;now;brown;cow' | cut -d ';' -f 1,3,4 --output-delimiter=' '
how brown cow