Delete text between patterns occurring in different lines

Question

I know that similar questions have been asked on this forum but, as far as I can see, none of them addressed the problem of patterns being in different lines. Namely, given a text file

( one ) ( two ) (

three

)

four

How may I delete everything that is between each '(' and ')' pair, even when the elements of the pair are on different lines? The desired result is

() () ()

four

score 2 · Answer 1 · answered Mar 08 '18 at 20:04

2

You can use perl: slurp the whole input as a single string, and use the s flag on the s/// command to indicate the newlines are to be treated as plain characters:

perl -0777 -pe 's/\(.*?\)/()/sg' <<END
( one ) ( two ) (

three

)

four
END

() () ()

four

answered Mar 08 '18 at 20:04

glenn jackman

85,964

Does this treat STDIN as a stream or read it all into memory? Also, is -0777 actually required? It's working without that flag for me. – Jay Taylor Mar 08 '18 at 20:24
It reads it into memory, and the -0777 option is required here. You'll have to demonstrate what you're doing to prove to me it isn't. – glenn jackman Mar 08 '18 at 20:30
Ah-ha! So if you pass the string like this: < <(echo 'something...)` then it works without -0777 flag, but when passing to stdin with a heredoc the flag is needed for it to work. Thanks Glenn. – Jay Taylor Mar 08 '18 at 21:31
In your process substitution, do you have any newlines? Or just a single echo statement? – glenn jackman Mar 08 '18 at 21:35
Slight correction: I used echo -e ... – Jay Taylor Mar 09 '18 at 00:39
So if there are no newlines in the input then that option has no visible effect – glenn jackman Mar 09 '18 at 00:56
Understood, thanks for patiently educating me Glenn! Cheers, Jay – Jay Taylor Mar 09 '18 at 18:07

Jay Taylor · Answer 2 · 2018-03-08T20:25:49.407

This can be solved with a simple state machine in Python.

#!/usr/bin/env python
# -*- coding: utf-8 -*-

import fileinput
import sys

active = True
for line in fileinput.input():
    for ch in line:
        if ch == '(':
            sys.stdout.write(ch)
            active = False
        elif ch == ')':
            sys.stdout.write(ch)
            active = True
        elif active:
            sys.stdout.write(ch)

Runnable Solution

Usage:

$ echo '( one ) ( two ) (

three

)

four' | python /tmp/statemachine.py

Output:

() () ()

four

score 0 · Answer 3 · answered Mar 08 '18 at 20:10

0

Python alternative:

python -c 'import sys,re; print(re.sub(r"\([^()]+\)","()",sys.stdin.read().strip()))' <file

The output:

() () ()

four

answered Mar 08 '18 at 20:10

RomanPerekhrest

30,212

score 0 · Answer 4 · answered Mar 08 '18 at 20:59

0

Using sed and will handle even if nested parentheses is there.

sed -z 's/[^()]*)/)/g' infile

Input:

( (zero) one ) ( two ) (

three

)

((((nested))here)end) last
four

Output:

( ()) () ()

(((()))) last
four

answered Mar 08 '18 at 20:59

αғsнιη

41,407

Delete text between patterns occurring in different lines

4 Answers4