text-processing-cut.md

Text Processing: cut

Character(s)

• single n-th character

$ echo foobar | cut -c4
> b

• multiple characters

$ echo foobar | cut -c1,4,6
> fbr

Substring

• head substring

$ echo foobar | cut -c-4
> foob

• tail substring

$ echo foobar | cut -c4-
> bar

• any substring

$ echo foobar | cut -c2-4
> oob

Characters and Substring

$ echo foobar | cut -c1,4-
> fbar

$ echo foobar | cut -c-3,5
> fooa

Excluding instead of Picking

$ echo foobar | cut --complement -c1
> oobar

$ echo foobar | cut --complement -c1-3,6
> ba

• to delete last characters use sed command

$ echo foobar | sed 's/..$//'
> foob

Characters, Bytes and Fields

Option	Meaning
-c	character(s)
-b	byte(s)
-f	field(s)

Getting Fields

$ cat data.txt
> John:25:New York
> Mark:58:Atlanta

$ cut -d: -f3 data.txt
> New York
> Atlanta

Reading stdout and Handling Tab Separators

• problem

$ ls -l
> total 2944
> -rw-rw-r--	1	john	pubs	4770	10731	Apr 4	23:26	notes.txt
> -rw-rw-r--	1	john	pubs	13580	0	Sep 11	08:01	script.sh

$ ls -l | cut -f9
> total 2944
> -rw-rw-r--	1	john	pubs	4770	10731	Apr 4	23:26	notes.txt
> -rw-rw-r--	1	john	pubs	13580	0	Sep 11	08:01	script.sh

• solution (change multiple spaces to single space with tr, and use space [instead of tab] as a delimiter with -d option)

$ ls -l | tr -s '  ' ' ' | cut -f9 -d' '
> notes.txt
> script.sh

Ignoring Lines without Separator (-s option)

$ cat file.txt
> data
> abc=123
> def=456

$ cat file.txt | cut  -f1 -d=
> data
> abc
> def

$ cat file.txt | cut -f1 -sd=
> abc
> def