RENAMING AND SCRATCHING TROUBLESOME FILES
(ADVANCED USERS)
Eventually, you may run across a file which has an odd filename, such as a comma
by itself
("
,
")
or one that includes a Shifted Space (a Shifted Space looks the same
as
a
regular space, but
if
a file with a space in its name won't load properly and all else
is
correct, it's probably a Shifted Space). Or perhaps you will find one that includes
nonprinting characters. Any
of
these can be troublesome. Comma files, for instance, are
an exception
to
the rule that no two files can have the same name. Since it shouldn't be
possible to make a file whose name
is
only a comma, the disk never expects you
to
do
it
again.
Files with a Shifted Space in their name can also be troublesome, because the disk
interprets the Shifted Space as signaling the end
of
the
file
name, and prints whatever
follows after the quotation mark that marks the end
of
a name in the directory. This
technique can be useful by allowing you
to
have a long file name, and making the disk
recognize a small part
of
it as being the same as the whole thing without using pattern-
matching characters.
In
any case,
if
you have a troublesome filename, you can use the CHR$O function to
specify troublesome characters without typing them directly. This may allow you to build
them into a RENAME command.
If
this fails, you may also use the pattern-matching
characters in a SCRATCH command. This gives you a way
to
specify the name without
using the troublesome characters at all, but also means loss
of
your file.
For example, if you have managed
to
create a file named
""MOVIES",
with an
extra quotation mark at the front
ofthe
file
name, you can rename it
to
"MOVIES"
using
the CHR$O equivalent
of
a quotation mark in the RENAME command:
PRINT#15, "R0:MOVIES
="
+CHR$(34) +
"MOVIES"
The CHR$(34) forces a quotation mark into the command string without upsetting
BASIC. The procedure for a file name that includes a Shifted Space
is
similar, but uses
CHR$(160).
In
cases where even this doesn't work, for example,
if
your diskette contains a
comma file, (one
named"
,")
you can get rid
of
it
this
way:
PRINT#15,
"S0:?"
This example deletes all files with one character names.
Depending on the exact problem, you may have
to
be very creative in choosing
pattern-matching characters that will affect only the desired file, and may have to rename
other files first
to
keep them from being scratched.
In
some cases, it may be easier
to
copy desired files
to
a different diskette and leave
the troublesome files behind.
COpy
The COPY command allows you to make a spare copy of any program or
file
on a
diskette. On a single drive like the 1571, the copy must be on the same diskette, which
means it must be given a different name from the file copied. It's also used
to
combine up
21
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