HP 3000 Manuals HP 3000 Manuals
PRINT--A Closer Look
The syntax diagram for the PRINT command is a little more complex than
the ones illustrated so far. It looks like this:
PRINT[[FILE=]filename][;[OUT=]outfile]
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|This is only part of the syntax diagram for PRINT. It has other |
|parameters, in addition to the ones shown here |
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The filename parameter is optional.
Notice, though, that you have the choice of whether to precede that
parameter with FILE=. (Within MPE/iX, there are historical and
engineering reasons for making this option available.)
The parameter outfile is optional, and so is the decision whether to
precede it with OUT=. Look carefully: the semicolon is required if you
choose to specify an outfile.
What is an outfile? It is an optional parameter. It permits you to
specify the destination for the contents of filename. Because it is an
optional parameter, outfile has a default action--in this case, a
destination for the contents of filename if you decide not to specify a
destination.
The default destination is your video screenl. From the computer's point
of view, your terminal is a file, too.
Suppose that you tried this:
PRINT TAXJAN;XYZReturn
What happens?
You have specified an outfile, so the contents of the file will not go to
the video terminal.
In this situation, the computer obligingly creates a temporary file
called XYZ. You could find it with LISTFILE @;TEMPReturn. This file will
disappear as soon as you log off.
You could transform this temporary file into a permanent file by using
the SAVE command:
SAVE XYZReturn
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| |
|Worth Knowing |
| |
|PURGE removes only one file at a time: PURGE G@Return will not remove|
|all of the files beginning with the letter "G." It will, instead, |
|generate a message informing you that you made an error. You must use|
|PURGE each time that you wish to remove a single file. That helps to |
|ensure that you make a conscious decision to erase a particular |
|file. |
| |
|MPE/iX has no command to "un-erase" a file. Backing up files is |
|vital. You can bring back a file from tape by using the RESTORE |
|command if the file was copied to tape with the STORE command, but |
|that does not help if the file that you erased has not been recorded |
|on tape. |
| |
|Regular and frequent backups give you the best protection against the |
|inadvertent erasure of a file. |
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