.TH CHMOD 2 
.SH NAME
chmod \- change mode of file
.SH SYNOPSIS
.B chmod(name, mode)
.br
.B char *name;
.SH DESCRIPTION
The file whose name
is given as the null-terminated string pointed to by
.I name
has its mode changed to
.IR mode .
Modes are constructed by ORing together some
combination of the following:
.PP
.RS
 04000 set user ID on execution
 02000 set group ID on execution
 01000 save text image after execution
 00400 read by owner
 00200 write by owner
 00100 execute (search on directory) by owner
 00070 read, write, execute (search) by group
 00007 read, write, execute (search) by others
.RE
.PP
If an executable file is set up for sharing
(\fB\-n\fR option of
.IR ld (1))
then mode 1000 prevents the system from
abandoning the swap-space image of the program-text portion
of the file when its last user
terminates.
Thus when the next user of the file executes it,
the text need not be read from the file
system but can simply be swapped in,
saving time.
Ability to set this bit is restricted to the super-user
since swap space is consumed
by the images; it is only worth while for heavily used commands.
.PP
Only the owner of a file (or the super-user) may change the mode.
Only the super-user can set the 1000 mode.
.SH "SEE ALSO"
chmod(1)
.SH DIAGNOSTIC
Zero is returned if the mode is changed;
\-1 is returned if
.I name
cannot be found or if current user
is neither the owner of the file nor the super-user.
.SH "ASSEMBLER (PDP-11)"
(chmod = 15.)
.br
.B sys chmod; name; mode