Read the section about glob in the perldoc perlport
of older perl versions if you are interested in these details.
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I've read the old an new docs and found only the following.
Old perl
perl-5.005_03 perlport
glob EXPR
glob
Globbing built-in, but only * and ? metacharacters are supported. (Mac OS)
Features depend on external perlglob.exe or perlglob.bat. May be
overridden with something like File::DosGlob, which is recommended. (Win32)
Globbing built-in, but only * and ? metacharacters are supported. Globbing
relies on operating system calls, which may return filenames in any
order. As most filesystems are case-insensitive, even ``sorted'' filenames
will not be in case-sensitive order. (RISC OS)
perl-5.005_03 perlop
Because globbing invokes a shell, it's often faster to call readdir() yourself
and do your own grep() on the filenames. Furthermore, due to its current
implementation of using a shell, the glob() routine may get ``Arg list too long''
errors (unless you've installed tcsh(1L) as /bin/csh).
perl-5.005_02 perlwin32
File Globbing
By default, perl spawns an external program to do file globbing. The install
process installs both a perlglob.exe and a perlglob.bat that perl can use for
this purpose. Note that with the default installation, perlglob.exe will
be found by the system before perlglob.bat.
Modern perl
perlport
glob
This operator is implemented via the File::Glob extension on most platforms.
See File::Glob for portability information.
perlwin32
File Globbing
By default, perl handles file globbing using the File::Glob extension, which
provides portable globbing.
And both old & new perls say:
Don't count on filename globbing.
Use opendir, readdir, and closedir instead.
Why can't I count on globbing in a modern perl? I found nothing in the docs. | [reply] |
The hint Don't count on filename globbing is meant short for Don't count on that all glob parameters on the command line will have been expanded by the calling shell for you, because, on Win32 (and likely VMS), the shell doesn't expand glob filespecs.
This is unrelated to the glob builtin, which "works" within the boundaries already given. The usage of File::Find and File::Find::Rule is still recommendable over manual reading or globbing via glob, because glob (and File::Glob) live under the assumption that whitespace is a sensible delimiter for glob patterns.
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