How to substitute multiple lines between delimiters

Question

Given the text example:

.... text ,..
{{{python
string1 = 'abcde'
string2 = '12345'
print(string1[[1:3]])
print(string2[[:-1]])
}}}
.... text ,..

The [[ and ]] also appear outside of {{{ too. Maybe there are spaces and tabs before {{{ and }}}.

I want to substitute all [[ and ]] into [ and ] between {{{ and }}}.

I need to write the result back to original file.

How can I do this? Will sed or awk work?

Answer 1

This might work for you:

sed -i '/\s*{{{/,/\s*}}}$/s/\[\(\[[^]]*\]\)\]/\1/g' file.txt

Answer 2

This should work:

awk '/{{{/,/}}}/ { gsub(/\[\[/,"[");gsub(/\]\]/,"]") } { print }'

Answer 3

I would use perl with a minor state variable. Assuming you saved the below as replace.pl:

#!/usr/bin/perl -w
my $inbraces=0;
while (<>) {
    /\{\{\{/ and $inbraces=1;
    $inbraces==1 && s/\[\[/[/;
    $inbraces==1 && s/]]/]/;
    /}}}/ and $inbraces=0;
    print $_;
}

You would want to run something like:

cat inputfile.txt | perl replace.pl > outputfile.pl

Basically, PERL loops over this for each line of input because of the while(<>) and for each line, if it matches the three-brace regex, it turns on and off whether the substitutions should take place. All the regexes are nearly identical to sed. Open braces are escaped when matching because of their keyword nature.