Lesson 4 Deleting Files

• the command to erase a file: PURGE

• recovering from an accidental file erasure

The PURGE command

The PURGE command erases a file. It erases only one file at a time. If you want to erase five files, you need to use the PURGE command five times.

Make sure that you are in the home group of your account. Recall from module 4 that the LISTUSER command shows which group is designated as your home group.

Enter:

   LISTUSERReturn

	NOTE: LISTUSER does not tell you which group you are currently in. It tells you only which group is designated as your home group.

To find out which group you are currently in, use the SHOWME command.

Enter:

   SHOWMEReturn

Use CHGROUP if necessary get into your home group.

To purge the file called NEWDRAFT, enter:

   PURGE NEWDRAFTReturn

Use LISTFILE to make sure that NEWDRAFT has been removed.

Now erase NXTDRAFT in the same way.

   PURGE NXTDRAFTReturn

If you try to erase a file that does not exist, you get an error message.

Try to erase the file QZQXQZ. What happens? (Of course, if the file does exist, it is erased. MPE/iX assumes that you know what you want to do when you issue a command.)

Recovering a file

The day will come when you accidentally erase a file that you need. It happens to almost everyone at some time.

MPE/iX does not provide an unerase command. MPE/iX assumes that you knew what you were doing when you erased a file.

There is a remedy. Your system operations personnel should perform regular system backups (storing all of the files on the system to tape).

For this exercise, suppose the following:

What would you do?

What is restored?

How much work is lost depends on two things:

	NOTE: System operation departments have different backup schedules, but all should perform regular file backups. Find out from your manager or system operations department what the backup schedule is. One day you may need to know.