regex - Perl search and replace substring -

how can search , replace substring using perl script?

for example --> txt1.txt

hi/hello #55 hi/hi #55 

how can search variable1 in txt1.txt, if found replace variable2. there can number after hashtag between 0-100. search "hi/hello" first , if found, replace whole content "hi/hello #(0-100)" "hi/hello #60;

mytry.txt

my $variable1="hi/hello #(0-100)"; $variable2="hi/hello #60; print "$short\n"; system(q{perl -pe"s|($env{variable1} *)#\d+|$env{variable2}|;" txt1.p4sm  > txt2.p4sm}); 

desiredoutput.txt

hi/hello #60 hi/hi #55 

what doing doesn't make sense, if inside of perl script don't shell out perform perl one-liner, write simple loop solve problem.

the easiest way create pattern matches like, perform substitution on line-by-line basis. example below uses data filehandle, can replaced filehandle pointing source file modify:

use strict;  use warnings;   $pattern = qr|(hi/hello) #\((\d{1,3})\)|; while ( $row = <data> ) {    # enforce restriction 0-100    if ( $row =~ m/$pattern/ && $2 >= 0 && $2 <= 100 ) {       # replace new suffix       print $row =~ s/$pattern/$1 #(60)/gr;         next;    }     print $row; }  __data__ hi/hello #(1) hi/hello #(10) hi/hello #(100) hi/hello #(101) 

output:

hi/hello #(60) hi/hello #(60) hi/hello #(60) hi/hello #(101) <- ignored because doesnt fall range [0, 100] 

regular expression explained:

(hi/hello) #\((\d{1,3})\) 

this regular expression matches , captures 2 pieces of data, prefix "hi/hello" , number inside of #(<number>). these stored in $1 , $2 respectively.