Using perl, create a regular expression for each of the following: 1. Replace al

Question

Using perl, create a regular expression for each of the following:

1. Replace all of the occurrences of a full line of # characters (ignoring leading or training spaces and lines with just 1 #) with the following: # ---------- #

2. Change any URL ending in .htm to end with .html

3. For any set of multiple words following an equal sign (=), place what follows the equal sign in quotes.

eg: a = bcd efg becomes a = "bcd efg"

eg: a = bcd remains a = bcd

4. Add a semicolon (;) to the end of every line

5. Every line beginning with a comment marker (#) and containing additional text should have one (and only one) space following the comment marker.

For example:
   # some text      becomes....
   # some text

6. Replace any pattern in the form of [__UPPER-CASE CHARACTERS__] with (lower-case characters)

ie: Open square bracket + two underscores + upper-case text + two underscores +  close square bracket

eg:[__SOMEDATA__] becomes [somedata]

7. Follow every "config section" with a comment that indicates the current section count:

For example:
[SVN] # Section: 1
[......] # Section: 2
etc.

Explanation / Answer

Hi,

Please find below the answers-

1.

#!/usr/bin/perl
use strict;
use warnings;

open my $fh,"<", "abc.txt" or die $!;
my $er='#';
while (my $line = <$fh>) {
$line =~ s/^(s+)$er+(s+)|' '/m /;
#$line =~ s/= ([a-zA-Z]+) ([a-zA-Z]+)+/= "$1 $2"/;
print $line;
}

2.

#!/usr/bin/perl
use strict;
use warnings;

open my $fh,"<", "abc.txt" or die $!;
my $er='#';
while (my $line = <$fh>) {
#$line =~ s/^$er+|' '/m/;
$line =~ s/.htm|' '/.html/;
print $line;
}

3.

#!/usr/bin/perl
use strict;
use warnings;

open my $fh,"<", "abc.txt" or die $!;
my $er='#';
while (my $line = <$fh>) {
#$line =~ s/^$er+|' '/m/;
$line =~ s/= ([a-zA-Z]+) ([a-zA-Z]+)+/= "$1 $2"/;
print $line;
}

4.

#!/usr/bin/perl
use strict;
use warnings;

open my $fh,"<", "abc.txt" or die $!;
my $er='#';
while (my $line = <$fh>) {
#$line =~ s/^(s+)$er+(s+)|' '/m /;
#$line =~ s/= ([a-zA-Z]+) ([a-zA-Z]+)+/= "$1 $2"/;
$line =~ s/(.*)|' '/$1 ;/;
print $line;
}

6.

#!/usr/bin/perl
use strict;
use warnings;

open my $fh,"<", "abc.txt" or die $!;
my $er='#';
while (my $line = <$fh>) {
#$line =~ s/^(s+)$er+(s+)|' '/m /;
$line =~ s/[__(.*)__]/[$1]/;
print $line;
}

Cheers,

Vinay Prakash Singh

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