Small bug:

#!/usr/bin/perl -wl

$s = "this is an\b\b not correct usage";
$s =~ s[.\cH][]g;

print $s;

print "and one's still there" if grep { ord == ord"\b" } split //,$s;
__END__
output:
this is  not correct usage
and one's still there
[download]

It looks correct at first glance, but the second backspace is still there.

Update: Much better. Only problem is in the case of a leading \b, you can get into an infinite loop. However only the regex needs alteration.

$s =~ s/(?:[^\cH]\cH|^\cH+)//g while ...
[download]

AWESOME, it sinks in slowly ;-)

This solves the problem from the poster below...

$s = "\bthis is an\b correct\b\b\b usage\b";
do 1  while ($s =~ s/(?:[^\cH]\cH|^\cH+)//g);
[download]

A matter of style, but I don't care for do 1 while ... since you could just do a while with an empty block. Anyhow, I decided to benchmark all three ways:

#!/usr/bin/perl -w

use Benchmark qw(cmpthese);
$s = "\bthis is an\b correct\b\b\b usage\b";

sub uk {
  $a = $s;
  $a =~ s[(?:[^\cH]\cH|^\cH)][]g while 1+index $a, chr(8);
  $a;
}

sub new1 {
  $a = $s;
  while ($a =~ s/(?:[^\cH]\cH|^\cH+)//g) {}
  $a;
}

sub smack {
  $a = $s;
  do 1 while ($a =~ s/(?:[^\cH]\cH|^\cH+)//g);
  $a;
}

cmpthese(-5,{uk=>\&uk,new1=>\&new1,smack=>\&smack});
$s x= 100;
cmpthese(-5,{uk=>\&uk,new1=>\&new1,smack=>\&smack});

__END__
Benchmark: running new1, smack, uk for at least 5 CPU seconds...
      new1:  5 wallclock secs ( 5.23 usr +  0.00 sys =  5.23 CPU) @ 31
+024.33/s (n=162393)
     smack:  6 wallclock secs ( 2.16 usr +  3.05 sys =  5.22 CPU) @ 29
+16.79/s (n=15222)
        uk:  5 wallclock secs ( 5.19 usr +  0.00 sys =  5.19 CPU) @ 36
+570.60/s (n=189710)
         Rate smack  new1    uk
smack  2917/s    --  -91%  -92%
new1  31024/s  964%    --  -15%
uk    36571/s 1154%   18%    --
Benchmark: running new1, smack, uk for at least 5 CPU seconds...
      new1:  6 wallclock secs ( 5.48 usr +  0.00 sys =  5.48 CPU) @ 36
+8.11/s (n=2016)
     smack:  6 wallclock secs ( 5.01 usr +  0.41 sys =  5.41 CPU) @ 32
+6.56/s (n=1768)
        uk:  5 wallclock secs ( 5.23 usr +  0.00 sys =  5.23 CPU) @ 46
+2.14/s (n=2419)
       Rate smack  new1    uk
smack 327/s    --  -11%  -29%
new1  368/s   13%    --  -20%
uk    462/s   42%   26%    --
[download]

For whatever reason, your version hits sys very hard. However, BrowserUK's version is the fastest of the pack.

Hope this helps.

antirice    
The first rule of Perl club is - use Perl
The ith rule of Perl club is - follow rule i - 1 for i > 1

Catering for multiline input and assuming backspaces at beginning of lines should simply be removed:

$s = "\b\bthis is an\b correct\b\b\b usage\b\n\b2nd\n\b\b3rd\n";
$s =~ s/^[\b]+//mg;
1 while $s =~ s/[^\b][\b]//g;
[download]

/-\

tr/\b//d would probably be the most efficient form but s/\010//g will also do the job. What is with all the .\010 and while(1)'s in the replies?

$_ = "hello\b\b\b\b\b\b\hello\b\b";
tr/\b//d;
print length($_), $/, $_, $/;
__DATA__
10
hellohello
[download]

You miss the point or I do.

When you remove the \b, you also have to remove the character behind it over which it backspaced. In your example, the final output should be something like "hel".

---

Examine what is said, not who speaks.

"Efficiency is intelligent laziness." -David Dunham
"When I'm working on a problem, I never think about beauty. I think only how to solve the problem. But when I have finished, if the solution is not beautiful, I know it is wrong." -Richard Buckminster Fuller
If I understand your problem, I can solve it! Of course, the same can be said for you.