3BSD/usr/man/man8/sticky.8

.TH STICKY 8
.SH NAME
sticky \- executable files with persistent text
.SH DESCRIPTION
While the `sticky bit', mode 01000 (see
.IR 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.)
.PP
Sharable files are made by the
.B \-n
and
.B \-i
options of
.IR ld (1).
.PP
To replace a sticky file that has been used do:
(1) Clear the sticky bit with
.IR 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; see the next paragraph
for a dodge.
(4) Set the sticky bit again.
Only the super-user can set the sticky bit.
.PP
To replace a sharable executable file while any user is
executing it do:
(1) Rename the directory entry for that file with
.IR mv (1).
(2) Install the new program with
.I cp,
.IR mv (1),
or otherwise.
(3) With
.I chown
and
.IR chmod (2),
set the mode of the new file to agree with that of the original
as necessary.
(4) Delete the old file when convenient.
.SH BUGS
Are self-evident.