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@(#)sticky.8 4.1 (Berkeley) 04/27/85

C 4 sticky - executable files with persistent text While the `sticky bit', mode 01000 (see chmod (2)), is set on a sharable executable file, the text of that file will not be removed from the system swap area. Thus the file does not have to be fetched from the file system upon each execution. As long as a copy remains in the swap area, the original text cannot be overwritten in the file system, nor can the file be deleted. (Directory entries can be removed so long as one link remains.)

Sharable files are made by the -n and -z options of ld (1).

To replace a sticky file that has been used do: (1) Clear the sticky bit with chmod (1). (2) Execute the old program to flush the swapped copy. This can be done safely even if others are using it. (3) Overwrite the sticky file. If the file is being executed by any process, writing will be prevented; it suffices to simply remove the file and then rewrite it, being careful to reset the owner and mode with chmod and chown (2). (4) Set the sticky bit again.

Only the super-user can set the sticky bit.

Are self-evident.

Is largely unnecessary on the VAX; matters only for large programs that will page heavily to start, since text pages are normally cached incore as long as possible after all instances of a text image exit.