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perl: printf indentation problem

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# 1  
Old 03-27-2008
Data perl: printf indentation problem
hi all,
im having a problem with using perl printf. my requirement is to print a string (like [OK]) at the right most end of the screen.
i tried this perl script, but it fails with an error;
Code:
#!/usr/bin/perl 

use strict;
use warnings;

my $scrW = 0;

my $str = `stty size`;   # get the screen character width 
$str =~ m/(\d+)\s*$/;    # extract the char width
$scrW = eval($1);           # put the char width in a varable $scrW

$scrW -=10;                     # reduce the char width by 10
printf "%($scrW)s\n", "abcde";

tried to use printf with a variable as indentation length, but fails.
this type of method works in bash.
does anyone have an idea ?

thankx.
# 2  
Old 03-27-2008
You don't need the eval, just assign $1 to $scrW. And take out the parentheses in the printf. You then need braces around the variable name to disambiguate the variable name from the traliing s, like ${scrW}s

If you subtract ten, you obviously don't use the entire screen width, but I guess you know that.
# 3  
Old 03-27-2008
Quote:
Originally Posted by era
You don't need the eval, just assign $1 to $scrW. And take out the parentheses in the printf. You then need braces around the variable name to disambiguate the variable name from the traliing s, like ${scrW}s

If you subtract ten, you obviously don't use the entire screen width, but I guess you know that.
thankx era for the quick reply,
i subtracted ten thinking that the length of the string im gonna print is 10. Smilie
what u said worked Smilie, but i still had to use the eval.
anyway, thankx for the solution.
# 4  
Old 03-27-2008
printf already does the subtraction for you; a positive number in %72s says pad with spaces as much as necessary to fill to the right up to, here, 72 characters width.
# 5  
Old 03-27-2008
Believe us, the eval really is redundant
Code:
$ perl -e '($c)=qx(stty size)=~/\d+\s+(\d+)/;printf"%${c}s\n",$ARGV[0]' Hello\ World
                                                                          Hello World

# 6  
Old 03-27-2008
sorry about my lack of understanding on how these functions work.
buffoonix`s method also works fine. thankx.
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