11-04-2008
shopt -s nullglob
Hi,
I am using BASH. In a directory there are files that match either of the following 2 patterns: [AST]*.L1A_[GL]AC* or S*.L1A_MLAC*
I would like to write a script that will include a for loop, where for each file in the directory, a certain function will be performed. For example:
for FILE in [AST]*.L1A_[GL]AC* S*.L1A_MLAC*; do
echo $FILE
done
The content of the directory will be random, and there are 3 potential scenarios: 1) Files of both patterns exist in the directory, 2) Only files of the 1st pattern exist, 3) Only files of the 2nd pattern exist. The last two scenarios are problematic as one of the patterns won't be matched, resulting in my script behaving oddly.
- I believe the way around this is to use the shopt -s nullglob option. Does anyone have any other ideas?
- MAIN QUESTION: Where in the code should I put the shopt -s nullglob and shopt -u nullglob? Of course the shopt -s nullglob should be set immediately before the the beginning of the for loop. But, can the shopt -u nullglob be immediately after the beginning of the for loop (ie):
shopt -s nullglob
for FILE in [AST]*.L1A_[GL]AC* S*.L1A_MLAC*; do
shopt -u nullglob
echo $FILE
done
OR after the conclusion of the for loop (ie):
shopt -s nullglob
for FILE in [AST]*.L1A_[GL]AC* S*.L1A_MLAC*; do
echo $FILE
done
shopt -u nullglob
The reason I ask is because I will of course have more complicated code within the for loop, and only want the shopt nullglob command to affect the pattern matching when calling the for loop.
Thanks for your help.
Mike
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LEARN ABOUT DEBIAN
template::alloy::compile
Template::Alloy::Compile(3pm) User Contributed Perl Documentation Template::Alloy::Compile(3pm)
NAME
Template::Alloy::Compile - Compile role - allows for compiling the AST to perl code
DESCRIPTION
The Template::Alloy::Compile role allows for taking the AST returned by the Parse role, and translating it into a perl code document. This
is in contrast Template::Alloy::Play which executes the AST directly.
TODO
o Translate compile_RAWPERL to actually output rather than calling play_RAWPERL.
ROLE METHODS
"compile_tree"
Takes an AST returned by parse_tree and translates it into perl code using functions stored in the $DIRECTIVES hashref.
A template that looked like the following:
Foo
[% GET foo %]
[% GET bar %]
Bar
would parse to the following perl code:
# Generated by Template::Alloy::Compile v1.001 on Thu Jun 7 12:58:33 2007
# From file /home/paul/bar.tt
my $blocks = {};
my $meta = {};
my $code = sub {
my ($self, $out_ref, $var) = @_;
$$out_ref .= 'Foo';
# "GET" Line 2 char 2 (chars 6 to 15)
$var = $self->play_expr(['foo', 0]);
$$out_ref .= defined($var) ? $var : $self->undefined_get(['foo', 0]);
# "GET" Line 3 char 2 (chars 22 to 31)
$var = $self->play_expr(['bar', 0]);
$$out_ref .= defined($var) ? $var : $self->undefined_get(['bar', 0]);
$$out_ref .= 'Bar';
return 1;
};
{
blocks => $blocks,
meta => $meta,
code => $code,
};
As you can see the output is quite a bit more complex than the AST, but under mod_perl conditions, the perl will run faster than
playing the AST each time.
"compile_expr"
Takes an AST variable or expression and returns perl code that can lookup the variable.
AUTHOR
Paul Seamons <paul at seamons dot com>
LICENSE
This module may be distributed under the same terms as Perl itself.
perl v5.10.1 2008-09-17 Template::Alloy::Compile(3pm)