cut

extract sections from lines of files

TLDR

Extract fields

$ cut -f [1,3] [file.txt]

Extract columns by character

$ cut -c [1-10] [file.txt]

Custom delimiter

$ cut -d [:] -f [1,7] [/etc/passwd]

Extract bytes

$ cut -b [1-5] [file.txt]

cut removes sections from each line of files. It extracts columns by character position, byte position, or field delimiter, making it useful for processing structured text data.The command is commonly used in shell scripts for parsing columnar data.

PARAMETERS

-f, --fields list

Select fields (delimiter-separated)

-c, --characters list

Select characters

-b, --bytes list

Select bytes

-d, --delimiter char

Field delimiter (default: TAB)

--output-delimiter string

Output delimiter

-s, --only-delimited

Don't print lines without delimiter

--complement

Complement the selection

RANGE SPECIFICATION

- N - Nth item- N- - From Nth to end- N-M - From Nth to Mth- -M - From beginning to Mth- N,M - Nth and Mth

WORKFLOW

$ # Extract first field (default TAB delimiter)
cut -f 1 data.tsv

# Extract multiple fields
cut -f 1,3,5 data.tsv

# CSV with custom delimiter
cut -d ',' -f 2 data.csv

# Extract username from /etc/passwd
cut -d ':' -f 1 /etc/passwd

# Extract characters 1-10
cut -c 1-10 file.txt

# Extract first 20 bytes
cut -b 1-20 file.txt

# Change output delimiter
cut -d ',' -f 1,2 --output-delimiter=':' data.csv

COMMON USES

Parse CSV:

$ cut -d ',' -f 2,4 data.csv

Extract columns from ps:

$ ps aux | cut -c 1-20,50-70

Get usernames:

$ cut -d ':' -f 1 /etc/passwd

Field range:

$ cut -f 2-5 data.tsv

INSTALL

sudo apt install coreutils

sudo dnf install coreutils

sudo pacman -S coreutils

sudo apk add coreutils

sudo zypper install coreutils

brew install coreutils

nix profile install nixpkgs#coreutils

CAVEATS

Cannot handle varying amounts of whitespace (use awk instead). Delimiter must be single character. Cannot reorder fields (use awk). No regular expression support. Quote handling in CSV requires other tools. Only operates on bytes/characters/fields, not by column width.