116 lines
2.6 KiB
Groff
116 lines
2.6 KiB
Groff
.\" @(#)newgrp.1 1.1 94/10/31 SMI; from S5R2
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.TH NEWGRP 1 "16 November 1987"
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.SH NAME
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newgrp \- log in to a new group
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.SH SYNOPSIS
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.B newgrp
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[
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.B \-
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] [
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.B group
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]
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.IX "newgrp command" "" "\fLnewgrp\fP \(em change group ID of user"
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.IX change "group ID of user \(em \fLnewgrp\fR"
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.IX "group ID" "\fLnewgrp\fR \(em change group ID of user"
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.SH DESCRIPTION
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.LP
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.B newgrp
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changes a user's group identification. Only the group-\s-1ID\s0 is changed;
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the user remains a member of all groups previously established by
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.B setgroups
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(see
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.BR getgroups (2V)).
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The user remains logged in
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and the current directory is unchanged,
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but the group-\s-1ID\s0 of newly-created files will be
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set to the new effective group-\s-1ID\s0 (see
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.BR open (2V)).
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The user is always given a new shell, replacing the current shell,
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regardless of whether
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.B newgrp
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terminated successfully or
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due to an error condition (such as an unknown group).
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.LP
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Exported variables retain their values after invoking
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.BR newgrp ;
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however, all unexported variables are either reset to their
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default value or set to null.
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System variables (such as
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.BR \s-1HOME\s0 ,
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.BR \s-1LOGNAME\s0 ,
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.BR \s-1PATH\s0 ,
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.BR \s-1SHELL\s0 ,
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.BR \s-1TERM\s0 ,
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and
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.BR \s-1USER\s0 ),
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unless exported by the system
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or explicitly exported by
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the user, are reset to default values.
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Note: the shell command
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.B export
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(see
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.BR sh (1))
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is the method to export variables, while the C shell command
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.B setenv
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(see
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.BR csh (1))
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implicitly exports its argument.
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.LP
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With no arguments,
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.B newgrp
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changes the group identification back to
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the group specified in the user's password file entry.
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.LP
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If the first argument to
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.B newgrp
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is a
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.RB ` \- ',
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the environment is changed to what would be expected if the
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user actually logged in again.
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.LP
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A password is demanded if the group has
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a password and the user does not,
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or if the group has a password and the user is not listed
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in
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.B /etc/group
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as being
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a member of that group.
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.SH FILES
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.PD 0
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.TP 20
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.B /etc/group
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system group file
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.TP
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.B /etc/passwd
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system password file
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.PD
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.SH SEE ALSO
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.BR csh (1),
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.BR login (1),
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.BR sh (1),
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.BR su (1V),
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.BR open (2V),
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.BR getgroups (2V),
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.BR initgroups (3),
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.BR environ (5V),
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.BR group (5),
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.BR passwd (5)
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.SH NOTES
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.LP
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For consistency with
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.B login
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naming rules (which do not allow 8-bit file names),
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group identifications cannot contain 8-bit characters.
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See
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.BR login (1)
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for explanations about why
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.B login
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is not 8-bit clean.
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.SH BUGS
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.LP
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There is no convenient way to enter a password into
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.BR /etc/group .
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Use of group passwords is not encouraged, because,
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by their very nature, they encourage poor security practices.
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Group passwords may disappear in the future.
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