HFS: File masks: Difference between revisions

From rejetto wiki
Jump to navigation Jump to search
No edit summary
Line 9: Line 9:
e ''*.gif''.<br>Il punto e virgola è utilizzato per unire maschere multiple essendo, infatti, un carattere'' "speciale"''.<br>Nelle maschere file possono esistere esclusivamente tre tipi di carattere speciale: ''';''' '''*''' e '''?'''.
e ''*.gif''.<br>Il punto e virgola è utilizzato per unire maschere multiple essendo, infatti, un carattere'' "speciale"''.<br>Nelle maschere file possono esistere esclusivamente tre tipi di carattere speciale: ''';''' '''*''' e '''?'''.


== The star (*) ==
== L'asterisco (*) ==


The star (also called "asterisk") stands for ''any string'' of characters. If the mask contains only the star, it matches ANY file.
The star (also called "asterisk") stands for ''any string'' of characters. If the mask contains only the star, it matches ANY file.
Line 23: Line 23:
but also ''A.jpg''.
but also ''A.jpg''.


== The question mark (?) ==
== Il punto interrogativo (?) ==


This stands for a ''single character''. Something like <tt>A?B</tt> matches any filename that is three characters long and starts with an A and ends with a B. The length is fixed to three characters because ? can be replaced by
This stands for a ''single character''. Something like <tt>A?B</tt> matches any filename that is three characters long and starts with an A and ends with a B. The length is fixed to three characters because ? can be replaced by
only one character. Thus the ? does not match the null string as the * does.
only one character. Thus the ? does not match the null string as the * does.

Revision as of 22:49, 10 January 2007

Cos'è?

Una maschera file ("file mask") denota un set di files.
Un esempio potrebbe essere il seguente: *.jpg;*.gif.
Questo modello denota ogni file con estensione .jpeg e .gif.
Ricorda che i caratteri usati nei nomi dei files non sono "case sensitive": per cui *.jpg e *.JPG (cioè scritto in minuscolo e/o maiuscolo) riferisce esattamente allo stesso set di files.

Come funziona?

L'esempio precedente mostra una doppia maschera file.
Presenta due elementi separati da punto e virgola (;): *.jpg e *.gif.
Il punto e virgola è utilizzato per unire maschere multiple essendo, infatti, un carattere "speciale".
Nelle maschere file possono esistere esclusivamente tre tipi di carattere speciale: ; * e ?.

L'asterisco (*)

The star (also called "asterisk") stands for any string of characters. If the mask contains only the star, it matches ANY file.

If you put an A before the star A*, it matches any file starting with an A.

If you put an A after the star *A, it matches any file ending with an A.

A*B matches any file starting with an A and ending with a B. The example above shows *.jpg : it matches any file ending with .jpg (that is, jpeg images). jpeg files are relatively unusual because they sometimes end with .jpeg and more rarely with .jpe . (The part of a filename that comes after the period is called the file "extension", and is normally limited to three characters.) You could use the mask .jp* to match all types of jpeg files.

The star also matches the null string: A*.jpg matches files like A1.jpg , Adfgg.jpg but also A.jpg.

Il punto interrogativo (?)

This stands for a single character. Something like A?B matches any filename that is three characters long and starts with an A and ends with a B. The length is fixed to three characters because ? can be replaced by only one character. Thus the ? does not match the null string as the * does.